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08fd123241
Exposed extracter OverwritePolicy, but it still defaults to the OverwritePolicy specified in the extracters configuration. git-svn-id: https://svn.alfresco.com/repos/alfresco-enterprise/alfresco/HEAD/root@6013 c4b6b30b-aa2e-2d43-bbcb-ca4b014f7261
759 lines
29 KiB
Java
759 lines
29 KiB
Java
/*
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* Copyright (C) 2005-2007 Alfresco Software Limited.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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* As a special exception to the terms and conditions of version 2.0 of
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* the GPL, you may redistribute this Program in connection with Free/Libre
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* and Open Source Software ("FLOSS") applications as described in Alfresco's
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* FLOSS exception. You should have recieved a copy of the text describing
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* the FLOSS exception, and it is also available here:
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* http://www.alfresco.com/legal/licensing"
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*/
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package org.alfresco.repo.content.metadata;
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import java.io.InputStream;
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import java.io.Serializable;
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import java.lang.reflect.Array;
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import java.util.Collection;
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import java.util.Collections;
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import java.util.HashMap;
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import java.util.HashSet;
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import java.util.Map;
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import java.util.Properties;
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import java.util.Set;
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import java.util.StringTokenizer;
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import org.alfresco.error.AlfrescoRuntimeException;
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import org.alfresco.service.cmr.repository.ContentIOException;
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import org.alfresco.service.cmr.repository.ContentReader;
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import org.alfresco.service.cmr.repository.MimetypeService;
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import org.alfresco.service.namespace.InvalidQNameException;
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import org.alfresco.service.namespace.QName;
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import org.apache.commons.logging.Log;
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import org.apache.commons.logging.LogFactory;
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/**
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* Support class for metadata extracters that support dynamic and config-driven
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* mapping between extracted values and model properties. Extraction is broken
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* up into two phases:
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* <ul>
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* <li>Extract ALL available metadata from the document.</li>
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* <li>Translate the metadata into system properties.</li>
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* </ul>
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* <p>
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* Migrating an existing extracter to use this class is straightforward:
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* <ul>
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* <li>
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* Construct the extracter providing a default set of supported mimetypes to this
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* implementation. This can be overwritten with configurations.
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* </li>
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* <li>
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* Implement the {@link extractInternal} method. This now returns a raw map of extracted
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* values keyed by document-specific property names. The <b>trimPut</b> method has
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* been replaced with an equivalent {@link #putRawValue(String, Serializable, Map)}.
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* </li>
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* <li>
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* Provide the default mapping of the document-specific properties to system-specific
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* properties as describe by the {@link #getDefaultMapping()} method. The simplest
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* is to provide the default mapping in a correlated <i>.properties</i> file.
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* </li>
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* <li>
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* Document, in the class-level javadoc, all the available properties that are extracted
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* along with their approximate meanings. Add to this, the default mappings.
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* </li>
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* </ul>
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*
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* @see #getDefaultMapping()
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* @see #extractRaw(ContentReader)
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* @see #setMapping(Map)
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*
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* @since 2.1
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*
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* @author Jesper Steen Møller
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* @author Derek Hulley
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*/
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abstract public class AbstractMappingMetadataExtracter implements MetadataExtracter
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{
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public static final String NAMESPACE_PROPERTY_PREFIX = "namespace.prefix.";
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protected static Log logger = LogFactory.getLog(AbstractMappingMetadataExtracter.class);
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private MetadataExtracterRegistry registry;
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private MimetypeService mimetypeService;
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private long extractionTime;
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private boolean initialized;
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private Set<String> supportedMimetypes;
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private OverwritePolicy overwritePolicy;
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private Map<String, Set<QName>> mapping;
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private boolean inheritDefaultMapping;
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protected AbstractMappingMetadataExtracter()
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{
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this(Collections.<String>emptySet());
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}
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/**
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* @param supportedMimetypes the set of mimetypes supported by default
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*/
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protected AbstractMappingMetadataExtracter(Set<String> supportedMimetypes)
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{
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this.supportedMimetypes = supportedMimetypes;
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// Set defaults
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overwritePolicy = OverwritePolicy.PRAGMATIC;
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mapping = null; // The default will be fetched
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inheritDefaultMapping = false; // Any overrides are complete
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initialized = false;
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}
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/**
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* Set the registry to register with. If this is not set, then the default
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* initialization will not auto-register the extracter for general use. It
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* can still be used directly.
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*
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* @param registry a metadata extracter registry
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*/
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public void setRegistry(MetadataExtracterRegistry registry)
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{
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this.registry = registry;
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}
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/**
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* @param mimetypeService the mimetype service. Set this if required.
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*/
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public void setMimetypeService(MimetypeService mimetypeService)
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{
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this.mimetypeService = mimetypeService;
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}
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/**
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* @return Returns the mimetype helper
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*/
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protected MimetypeService getMimetypeService()
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{
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return mimetypeService;
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}
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/**
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* Set the mimetypes that are supported by the extracter.
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*
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* @param supportedMimetypes
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*/
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public void setSupportedMimetypes(Collection<String> supportedMimetypes)
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{
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this.supportedMimetypes.clear();
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this.supportedMimetypes.addAll(supportedMimetypes);
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}
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/**
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* {@inheritDoc}
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*
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* @see #setSupportedMimetypes(Collection)
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*/
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public boolean isSupported(String sourceMimetype)
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{
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return supportedMimetypes.contains(sourceMimetype);
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}
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/**
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* @return Returns <code>1.0</code> if the mimetype is supported, otherwise <tt>0.0</tt>
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*
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* @see #isSupported(String)
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*/
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public double getReliability(String mimetype)
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{
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return isSupported(mimetype) ? 1.0D : 0.0D;
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}
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/**
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* @param overwritePolicy the policy to apply when there are existing system properties
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*/
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public void setOverwritePolicy(OverwritePolicy overwritePolicy)
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{
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this.overwritePolicy = overwritePolicy;
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}
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/**
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* Set if the property mappings augment or override the mapping generically provided by the
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* extracter implementation. The default is <tt>false</tt>, i.e. any mapping set completely
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* replaces the {@link #getDefaultMapping() default mappings}.
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*
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* @param inheritDefaultMapping <tt>true</tt> to add the configured mapping
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* to the list of default mappings.
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*
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* @see #getDefaultMapping()
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* @see #setMapping(Map)
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* @see #setMappingProperties(Properties)
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*/
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public void setInheritDefaultMapping(boolean inheritDefaultMapping)
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{
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this.inheritDefaultMapping = inheritDefaultMapping;
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}
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/**
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* Set the mapping from document metadata to system metadata. It is possible to direct
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* an extracted document property to several system properties. The conversion between
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* the document property types and the system property types will be done by the
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* {@link org.alfresco.service.cmr.repository.datatype.DefaultTypeConverter default converter}.
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*
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* @param mapping a mapping from document metadata to system metadata
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*/
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public void setMapping(Map<String, Set<QName>> mapping)
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{
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this.mapping = mapping;
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}
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/**
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* Set the properties that contain the mapping from document metadata to system metadata.
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* This is an alternative to the {@link #setMapping(Map)} method. Any mappings already
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* present will be cleared out.
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*
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* The property mapping is of the form:
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* <pre>
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* # Namespaces prefixes
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* namespace.prefix.cm=http://www.alfresco.org/model/content/1.0
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* namespace.prefix.my=http://www....com/alfresco/1.0
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*
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* # Mapping
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* editor=cm:author, my:editor
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* title=cm:title
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* user1=cm:summary
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* user2=cm:description
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* </pre>
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* The mapping can therefore be from a single document property onto several system properties.
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*
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* @param mappingProperties the properties that map document properties to system properties
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*/
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public void setMappingProperties(Properties mappingProperties)
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{
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mapping = readMappingProperties(mappingProperties);
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}
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/**
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* Helper method for derived classes to obtain the mappings that will be applied to raw
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* values. This should be called after initialization in order to guarantee the complete
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* map is given.
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* <p>
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* Normally, the list of properties that can be extracted from a document is fixed and
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* well-known - in that case, just extract everything. But Some implementations may have
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* an extra, indeterminate set of values available for extraction. If the extraction of
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* these runtime parameters is expensive, then the keys provided by the return value can
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* be used to extract values from the documents. The metadata extraction becomes fully
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* configuration-driven, i.e. declaring further mappings will result in more values being
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* extracted from the documents.
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* <p>
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* Most extractors will not be using this method. For an example of its use, see the
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* {@linkplain OpenDocumentMetadataExtracter OpenDocument extractor}, which uses the mapping
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* to select specific user properties from a document.
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*/
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protected final Map<String, Set<QName>> getMapping()
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{
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if (!initialized)
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{
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throw new UnsupportedOperationException("The complete mapping is only available after initialization.");
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}
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return Collections.unmodifiableMap(mapping);
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}
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/**
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* A utility method to read mapping properties from a resource file and convert to the map form.
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*
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* @param propertiesUrl A standard Properties file URL location
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*
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* @see #setMappingProperties(Properties)
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*/
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protected Map<String, Set<QName>> readMappingProperties(String propertiesUrl)
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{
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InputStream is = null;
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try
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{
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is = getClass().getClassLoader().getResourceAsStream(propertiesUrl);
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if(is == null)
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{
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throw new AlfrescoRuntimeException(
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"Metadata Extracter mapping properties not found: \n" +
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" Extracter: " + this + "\n" +
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" Bundle: " + propertiesUrl);
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}
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Properties props = new Properties();
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props.load(is);
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// Process it
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Map<String, Set<QName>> map = readMappingProperties(props);
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// Done
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if (logger.isDebugEnabled())
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{
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logger.debug("Loaded mapping properties from resource: " + propertiesUrl);
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}
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return map;
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}
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catch (Throwable e)
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{
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throw new AlfrescoRuntimeException(
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"Unable to load properties file to read extracter mapping properties: \n" +
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" Extracter: " + this + "\n" +
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" Bundle: " + propertiesUrl,
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e);
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}
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finally
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{
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if (is != null)
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{
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try { is.close(); } catch (Throwable e) {}
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}
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}
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}
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/**
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* A utility method to convert mapping properties to the Map form.
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*
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* @see #setMappingProperties(Properties)
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*/
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protected Map<String, Set<QName>> readMappingProperties(Properties mappingProperties)
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{
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Map<String, String> namespacesByPrefix = new HashMap<String, String>(5);
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// Get the namespaces
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for (Map.Entry entry : mappingProperties.entrySet())
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{
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String propertyName = (String) entry.getKey();
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if (propertyName.startsWith(NAMESPACE_PROPERTY_PREFIX))
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{
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String prefix = propertyName.substring(17);
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String namespace = (String) entry.getValue();
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namespacesByPrefix.put(prefix, namespace);
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}
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}
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// Create the mapping
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Map<String, Set<QName>> convertedMapping = new HashMap<String, Set<QName>>(17);
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for (Map.Entry entry : mappingProperties.entrySet())
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{
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String documentProperty = (String) entry.getKey();
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String qnamesStr = (String) entry.getValue();
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if (documentProperty.startsWith(NAMESPACE_PROPERTY_PREFIX))
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{
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// Ignore these now
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continue;
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}
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// Create the entry
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Set<QName> qnames = new HashSet<QName>(3);
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convertedMapping.put(documentProperty, qnames);
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// The to value can be a list of QNames
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StringTokenizer tokenizer = new StringTokenizer(qnamesStr, ",");
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while (tokenizer.hasMoreTokens())
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{
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String qnameStr = tokenizer.nextToken().trim();
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// Check if we need to resolve a namespace reference
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int index = qnameStr.indexOf(QName.NAMESPACE_PREFIX);
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if (index > -1 && qnameStr.charAt(0) != QName.NAMESPACE_BEGIN)
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{
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String prefix = qnameStr.substring(0, index);
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String suffix = qnameStr.substring(index + 1);
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// It is prefixed
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String uri = namespacesByPrefix.get(prefix);
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if (uri == null)
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{
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throw new AlfrescoRuntimeException(
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"No prefix mapping for extracter property mapping: \n" +
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" Extracter: " + this + "\n" +
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" Mapping: " + entry);
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}
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qnameStr = QName.NAMESPACE_BEGIN + uri + QName.NAMESPACE_END + suffix;
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}
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try
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{
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QName qname = QName.createQName(qnameStr);
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// Add it to the mapping
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qnames.add(qname);
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}
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catch (InvalidQNameException e)
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{
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throw new AlfrescoRuntimeException(
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"Can't create metadata extracter property mapping: \n" +
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" Extracter: " + this + "\n" +
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" Mapping: " + entry);
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}
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}
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if (logger.isDebugEnabled())
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{
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logger.debug("Added mapping from " + documentProperty + " to " + qnames);
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}
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}
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// Done
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return convertedMapping;
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}
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/**
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* Registers this instance of the extracter with the registry. This will call the
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* {@link #init()} method and then register if the registry is available.
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*
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* @see #setRegistry(MetadataExtracterRegistry)
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* @see #init()
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*/
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public final void register()
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{
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init();
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// Register the extracter, if necessary
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if (registry != null)
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{
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registry.register(this);
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}
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else
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{
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logger.warn("No registry provided. Not registering: " + this);
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}
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}
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/**
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* Provides a hook point for implementations to perform initialization. The base
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* implementation must be invoked or the extracter will fail during extraction.
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* The {@link #getDefaultMapping() default mappings} will be requested during
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* initialization.
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*/
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protected void init()
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{
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Map<String, Set<QName>> defaultMapping = getDefaultMapping();
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if (defaultMapping == null)
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{
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throw new AlfrescoRuntimeException("The metadata extracter must provide a default mapping: " + this);
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}
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// Was a mapping explicitly provided
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if (mapping == null)
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{
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// No mapping, so use the default
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mapping = defaultMapping;
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}
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else if (inheritDefaultMapping)
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{
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// Merge the default mapping into the configured mapping
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for (String documentKey : defaultMapping.keySet())
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{
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Set<QName> systemQNames = mapping.get(documentKey);
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if (systemQNames == null)
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{
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systemQNames = new HashSet<QName>(3);
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mapping.put(documentKey, systemQNames);
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}
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Set<QName> defaultQNames = defaultMapping.get(documentKey);
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systemQNames.addAll(defaultQNames);
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}
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}
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// Were there any mappings
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if (mapping.size() == 0)
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{
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logger.warn(
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"There are no property mappings for the metadata extracter.\n" +
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" Nothing will be extracted by: " + this);
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}
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// Done
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initialized = true;
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}
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/** {@inheritDoc} */
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public long getExtractionTime()
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{
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return extractionTime;
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}
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/**
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* Checks if the mimetype is supported.
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*
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* @param reader the reader to check
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* @throws AlfrescoRuntimeException if the mimetype is not supported
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*/
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protected void checkIsSupported(ContentReader reader)
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{
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String mimetype = reader.getMimetype();
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if (!isSupported(mimetype))
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{
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throw new AlfrescoRuntimeException(
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"Metadata extracter does not support mimetype: \n" +
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" reader: " + reader + "\n" +
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" supported: " + supportedMimetypes + "\n" +
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" extracter: " + this);
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}
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}
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/**
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* {@inheritDoc}
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*/
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public final Map<QName, Serializable> extract(ContentReader reader, Map<QName, Serializable> destination)
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{
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return extract(reader, this.overwritePolicy, destination, this.mapping);
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}
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/**
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* {@inheritDoc}
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*/
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public final Map<QName, Serializable> extract(
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ContentReader reader,
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OverwritePolicy overwritePolicy,
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Map<QName, Serializable> destination)
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{
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return extract(reader, overwritePolicy, destination, this.mapping);
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}
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/**
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* {@inheritDoc}
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*/
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public final Map<QName, Serializable> extract(
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ContentReader reader,
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OverwritePolicy overwritePolicy,
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Map<QName, Serializable> destination,
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Map<String, Set<QName>> mapping)
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{
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// Done
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if (logger.isDebugEnabled())
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{
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logger.debug("Starting metadata extraction: \n" +
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" reader: " + reader + "\n" +
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" extracter: " + this);
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}
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if (!initialized)
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{
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throw new AlfrescoRuntimeException(
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"Metadata extracter not initialized.\n" +
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" Call the 'register' method on: " + this + "\n" +
|
|
" Implementations of the 'init' method must call the base implementation.");
|
|
}
|
|
// check the reliability
|
|
checkIsSupported(reader);
|
|
|
|
Map<QName, Serializable> changedProperties = null;
|
|
try
|
|
{
|
|
Map<String, Serializable> rawMetadata = extractRaw(reader);
|
|
// Convert to system properties (standalone)
|
|
Map<QName, Serializable> systemProperties = mapRawToSystem(rawMetadata);
|
|
// Now use the proper overwrite policy
|
|
changedProperties = overwritePolicy.applyProperties(systemProperties, destination);
|
|
}
|
|
catch (Throwable e)
|
|
{
|
|
throw new ContentIOException("Metadata extraction failed: \n" +
|
|
" reader: " + reader,
|
|
e);
|
|
}
|
|
finally
|
|
{
|
|
// check that the reader was closed (if used)
|
|
if (reader.isChannelOpen())
|
|
{
|
|
logger.error("Content reader not closed by metadata extracter: \n" +
|
|
" reader: " + reader + "\n" +
|
|
" extracter: " + this);
|
|
}
|
|
}
|
|
|
|
// Done
|
|
if (logger.isDebugEnabled())
|
|
{
|
|
logger.debug("Completed metadata extraction: \n" +
|
|
" reader: " + reader + "\n" +
|
|
" extracter: " + this + "\n" +
|
|
" changed: " + changedProperties);
|
|
}
|
|
return changedProperties;
|
|
}
|
|
|
|
/**
|
|
*
|
|
* @param rawMetadata Metadata keyed by document properties
|
|
* @return Returns the metadata keyed by the system properties
|
|
*/
|
|
private Map<QName, Serializable> mapRawToSystem(Map<String, Serializable> rawMetadata)
|
|
{
|
|
Map<QName, Serializable> systemProperties = new HashMap<QName, Serializable>(rawMetadata.size() * 2 + 1);
|
|
for (Map.Entry<String, Serializable> entry : rawMetadata.entrySet())
|
|
{
|
|
String documentKey = entry.getKey();
|
|
// Check if there is a mapping for this
|
|
if (!mapping.containsKey(documentKey))
|
|
{
|
|
// No mapping - ignore
|
|
continue;
|
|
}
|
|
Serializable documentValue = entry.getValue();
|
|
Set<QName> systemQNames = mapping.get(documentKey);
|
|
for (QName systemQName : systemQNames)
|
|
{
|
|
systemProperties.put(systemQName, documentValue);
|
|
}
|
|
}
|
|
// Done
|
|
if (logger.isDebugEnabled())
|
|
{
|
|
logger.debug(
|
|
"Converted extracted raw values to system values: \n" +
|
|
" Raw Properties: " + rawMetadata + "\n" +
|
|
" System Properties: " + systemProperties);
|
|
}
|
|
return systemProperties;
|
|
}
|
|
|
|
/**
|
|
* Adds a value to the map if it is non-trivial. A value is trivial if
|
|
* <ul>
|
|
* <li>it is null</li>
|
|
* <li>it is an empty string value after trimming</li>
|
|
* <li>it is an empty collection</li>
|
|
* <li>it is an empty array</li>
|
|
* </ul>
|
|
* String values are trimmed before being put into the map.
|
|
* Otherwise, it is up to the extracter to ensure that the value is a <tt>Serializable</tt>.
|
|
* It is not appropriate to implicitly convert values in order to make them <tt>Serializable</tt>
|
|
* - the best conversion method will depend on the value's specific meaning.
|
|
*
|
|
* @param key the destination key
|
|
* @param value the serializable value
|
|
* @param destination the map to put values into
|
|
* @return Returns <tt>true</tt> if set, otherwise <tt>false</tt>
|
|
*/
|
|
protected boolean putRawValue(String key, Serializable value, Map<String, Serializable> destination)
|
|
{
|
|
if (value == null)
|
|
{
|
|
return false;
|
|
}
|
|
if (value instanceof String)
|
|
{
|
|
String valueStr = ((String) value).trim();
|
|
if (valueStr.length() == 0)
|
|
{
|
|
return false;
|
|
}
|
|
else
|
|
{
|
|
// Keep the trimmed value
|
|
value = valueStr;
|
|
}
|
|
}
|
|
else if (value instanceof Collection)
|
|
{
|
|
Collection valueCollection = (Collection) value;
|
|
if (valueCollection.isEmpty())
|
|
{
|
|
return false;
|
|
}
|
|
}
|
|
else if (value.getClass().isArray())
|
|
{
|
|
if (Array.getLength(value) == 0)
|
|
{
|
|
return false;
|
|
}
|
|
}
|
|
// It passed all the tests
|
|
destination.put(key, value);
|
|
return true;
|
|
}
|
|
|
|
/**
|
|
* Helper method to fetch a clean map into which raw values can be dumped.
|
|
*
|
|
* @return Returns an empty map
|
|
*/
|
|
protected final Map<String, Serializable> newRawMap()
|
|
{
|
|
return new HashMap<String, Serializable>(17);
|
|
}
|
|
|
|
/**
|
|
* This method provides a <i>best guess</i> of where to store the values extracted
|
|
* from the documents. The list of properties mapped by default need <b>not</b>
|
|
* include all properties extracted from the document; just the obvious set of mappings
|
|
* need be supplied.
|
|
* Implementations must either provide the default mapping properties in the expected
|
|
* location or override the method to provide the default mapping.
|
|
* <p>
|
|
* The default implementation looks for the default mapping file in the location
|
|
* given by the class name and <i>.properties</i>. If the extracter's class is
|
|
* <b>x.y.z.MyExtracter</b> then the default properties will be picked up at
|
|
* <b>classpath:/x/y/z/MyExtracter.properties</b>.
|
|
* Inner classes are supported, but the '$' in the class name is replaced with '-', so
|
|
* default properties for <b>x.y.z.MyStuff$MyExtracter</b> will be located using
|
|
* <b>x.y.z.MyStuff-MyExtracter.properties</b>.
|
|
* <p>
|
|
* The default mapping implementation should include thorough Javadocs so that the
|
|
* system administrators can accurately determine how to best enhance or override the
|
|
* default mapping.
|
|
* <p>
|
|
* If the default mapping is declared in a properties file other than the one named after
|
|
* the class, then the {@link #readMappingProperties(String)} method can be used to quickly
|
|
* generate the return value:
|
|
* <pre><code>
|
|
* protected Map<<String, Set<QName>> getDefaultMapping()
|
|
* {
|
|
* return readMappingProperties(DEFAULT_MAPPING);
|
|
* }
|
|
* </code></pre>
|
|
* The map can also be created in code either statically or during the call.
|
|
*
|
|
* @return Returns the default, static mapping. It may not be null.
|
|
*
|
|
* @see #setInheritDefaultMapping(boolean inherit)
|
|
*/
|
|
protected Map<String, Set<QName>> getDefaultMapping()
|
|
{
|
|
String className = this.getClass().getName();
|
|
// Replace $
|
|
className = className.replace('$', '-');
|
|
// Replace .
|
|
className = className.replace('.', '/');
|
|
// Append .properties
|
|
String propertiesUrl = className + ".properties";
|
|
// Attempt to load the properties
|
|
return readMappingProperties(propertiesUrl);
|
|
}
|
|
|
|
/**
|
|
* Override to provide the raw extracted metadata values. An extracter should extract
|
|
* as many of the available properties as is realistically possible. Even if the
|
|
* {@link #getDefaultMapping() default mapping} doesn't handle all properties, it is
|
|
* possible for each instance of the extracter to be configured differently and more or
|
|
* less of the properties may be used in different installations.
|
|
* <p>
|
|
* Raw values must not be trimmed or removed for any reason. Null values and empty
|
|
* strings are
|
|
* <ul>
|
|
* <li><b>Null:</b> Removed</li>
|
|
* <li><b>Empty String:</b> Passed to the {@link OverwritePolicy}</li>
|
|
* <li><b>Non Serializable:</b> Converted to String or fails if that is not possible</li>
|
|
* </ul>
|
|
* <p>
|
|
* Properties extracted and their meanings and types should be thoroughly described in
|
|
* the class-level javadocs of the extracter implementation, for example:
|
|
* <pre>
|
|
* <b>editor:</b> - the document editor --> cm:author
|
|
* <b>title:</b> - the document title --> cm:title
|
|
* <b>user1:</b> - the document summary
|
|
* <b>user2:</b> - the document description --> cm:description
|
|
* <b>user3:</b> -
|
|
* <b>user4:</b> -
|
|
* </pre>
|
|
*
|
|
* @param reader the document to extract the values from. This stream provided by
|
|
* the reader must be closed if accessed directly.
|
|
* @return Returns a map of document property values keyed by property name.
|
|
* @throws All exception conditions can be handled.
|
|
*
|
|
* @see #getDefaultMapping()
|
|
*/
|
|
protected abstract Map<String, Serializable> extractRaw(ContentReader reader) throws Throwable;
|
|
}
|