cmsjspvfsaccessbean.java

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/*
 * File   : $Source: /usr/local/cvs/opencms/src/org/opencms/jsp/util/CmsJspVfsAccessBean.java,v $
 * Date   : $Date: 2007-09-05 11:19:35 $
 * Version: $Revision: 1.4 $
 *
 * This library is part of OpenCms -
 * the Open Source Content Management System
 *
 * Copyright (c) 2002 - 2007 Alkacon Software GmbH (http://www.alkacon.com)
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * For further information about Alkacon Software, please see the
 * company website: http://www.alkacon.com
 *
 * For further information about OpenCms, please see the
 * project website: http://www.opencms.org
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

package org.opencms.jsp.util;

import org.opencms.file.CmsObject;
import org.opencms.file.CmsRequestContext;
import org.opencms.file.CmsResource;
import org.opencms.file.types.CmsResourceTypeXmlContent;
import org.opencms.file.types.CmsResourceTypeXmlPage;
import org.opencms.main.CmsException;
import org.opencms.main.OpenCms;
import org.opencms.staticexport.CmsLinkManager;

import java.util.Collections;
import java.util.HashMap;
import java.util.Map;

import org.apache.commons.collections.Transformer;
import org.apache.commons.collections.map.LazyMap;

/**
 * Provides utility methods that allow convenient access to the OpenCms VFS, 
 * indented to be used from a JSP with the JSTL or EL.<p>
 * 
 * @author Alexander Kandzior
 * 
 * @version $Revision: 1.4 $ 
 * 
 * @since 7.0.2
 * 
 * @see CmsJspContentAccessBean
 */
public final class CmsJspVfsAccessBean {

    /**
     * Provides Booleans that indicate if a specified resource exists in the OpenCms VFS,  
     * the input is used as String for the resource name to read.<p>
     */
    public class CmsExistsResourceTransformer implements Transformer {

        /**
         * @see org.apache.commons.collections.Transformer#transform(java.lang.Object)
         */
        public Object transform(Object input) {

            return Boolean.valueOf(getReadResource().get(input) != null);
        }
    }

    /**
     * Provides Booleans that indicate if a specified resource exists in the OpenCms VFS
     * and is of type XML content or XML page,
     * the input is used as String for the resource name to read.<p>
     */
    public class CmsExistsXmlTransformer implements Transformer {

        /**
         * @see org.apache.commons.collections.Transformer#transform(java.lang.Object)
         */
        public Object transform(Object input) {

            // first read the resource using the lazy map 
            CmsResource resource = (CmsResource)getReadResource().get(input);
            return Boolean.valueOf((resource != null)
                && (CmsResourceTypeXmlPage.isXmlPage(resource) || CmsResourceTypeXmlContent.isXmlContent(resource)));
        }
    }

    /**
     * Transformer that a properties of a resource from the OpenCms VFS, 
     * the input is used as String for the property name to read.<p>
     */
    public class CmsPropertyLoaderSingleTransformer implements Transformer {

        /** The resource where the properties are read from. */
        private CmsResource m_resource;

        /** Indicates if properties should be searched when loaded. */
        private boolean m_search;

        /**
         * Creates a new property loading Transformer.<p>
         * 
         * @param resource the resource where the properties are read from
         * @param search indicates if properties should be searched when loaded
         */
        public CmsPropertyLoaderSingleTransformer(CmsResource resource, boolean search) {

            m_resource = resource;
            m_search = search;
        }

        /**
         * @see org.apache.commons.collections.Transformer#transform(java.lang.Object)
         */
        public Object transform(Object input) {

            String result;
            try {
                // read the properties of the requested resource
                result = getCmsObject().readPropertyObject(m_resource, String.valueOf(input), m_search).getValue();
            } catch (CmsException e) {
                // in case of any error we assume the property does not exist
                result = null;
            }
            return result;
        }
    }

    /**
     * Transformer that loads properties of a resource from the OpenCms VFS with another lazy map, 
     * the input is used as String for the resource name to read.<p>
     */
    public class CmsPropertyLoaderTransformer implements Transformer {

        /** Indicates if properties should be searched when loaded. */
        private boolean m_search;

        /**
         * Creates a new property loading Transformer.<p>
         * 
         * @param search indicates if properties should be searched when loaded
         */
        public CmsPropertyLoaderTransformer(boolean search) {

            m_search = search;
        }

        /**
         * @see org.apache.commons.collections.Transformer#transform(java.lang.Object)
         */
        public Object transform(Object input) {

            Map result = null;
            // first read the resource using the lazy map 
            CmsResource resource = (CmsResource)getReadResource().get(input);
            if (resource != null) {
                result = LazyMap.decorate(new HashMap(), new CmsPropertyLoaderSingleTransformer(resource, m_search));
            }
            // result may still be null
            return (result == null) ? Collections.EMPTY_MAP : result;
        }
    }

    /**
     * Transformer that loads a resource from the OpenCms VFS, 
     * the input is used as String for the resource name to read.<p>
     */
    public class CmsResourceLoaderTransformer implements Transformer {

        /**
         * @see org.apache.commons.collections.Transformer#transform(java.lang.Object)
         */
        public Object transform(Object input) {

            CmsResource result;
            try {
                // read the requested resource
                result = CmsJspElFunctions.convertResource(getCmsObject(), input);
            } catch (CmsException e) {
                // unable to read resource, return null
                result = null;
            }
            return result;
        }
    }

    /**
     * Transformer that calculates links to resources in the OpenCms VFS, 
     * the input is used as String for the resource name to use as link target.<p>
     * 
     * This is using the same logic as 
     * {@link org.opencms.jsp.CmsJspTagLink#linkTagAction(String, javax.servlet.ServletRequest)}.<p>
     */
    public class CmsVfsLinkTransformer implements Transformer {

        /**
         * @see org.apache.commons.collections.Transformer#transform(java.lang.Object)
         */
        public Object transform(Object input) {

            return OpenCms.getLinkManager().substituteLink(
                getCmsObject(),
                CmsLinkManager.getAbsoluteUri(String.valueOf(input), getCmsObject().getRequestContext().getUri()));
        }
    }

    /**
     * Provides XML content access beans for VFS resources.<p>
     */
    public class CmsXmlContentAccessTransformer implements Transformer {

        /**
         * @see org.apache.commons.collections.Transformer#transform(java.lang.Object)
         */
        public Object transform(Object input) {

            CmsJspContentAccessBean result = null;
            // first read the resource using the lazy map 
            CmsResource resource = (CmsResource)getReadResource().get(input);
            if ((resource != null)
                && (CmsResourceTypeXmlPage.isXmlPage(resource) || CmsResourceTypeXmlContent.isXmlContent(resource))) {
                // make sure we have a resource that really is an XML content
                result = new CmsJspContentAccessBean(getCmsObject(), resource);
            }
            return result;
        }
    }

    /** Request context attribute for indicating the model file for a create resource operation. */
    public static final String ATTRIBUTE_VFS_ACCESS_BEAN = CmsJspVfsAccessBean.class.getName() + ".VFS_ACCESS_BEAN";

    /** The OpenCms context of the current user. */
    private CmsObject m_cms;

    /** Contains booleans that indicate if a resource exists in the VFS. */
    private Map m_existsResource;

    /** Contains booleans that indicate if a resource exists and is an XML content. */
    private Map m_existsXml;

    /** Links calculated for the OpenCms VFS. */
    private Map m_links;

    /** Properties loaded from the OpenCms VFS. */
    private Map m_properties;

    /** Properties loaded from the OpenCms VFS with search. */
    private Map m_propertiesSearch;

    /** Resources loaded from the OpenCms VFS. */
    private Map m_resources;

    /** XML contents read from the VFS. */
    private Map m_xmlContent;

    /**
     * Creates a new context bean using the OpenCms context of the current user.<p>
     * 
     * @param cms the OpenCms context of the current user
     */
    private CmsJspVfsAccessBean(CmsObject cms) {

        m_cms = cms;
    }

    /**
     * Creates a new instance of the JSP VFS access utility bean.<p>
     * 
     * To prevent multiple creations of the bean during a request, the OpenCms request context 
     * attributes are used to cache the created VFS access utility bean.<p>
     * 
     * @param cms the current OpenCms user context
     * 
     * @return a new instance of the JSP VFS access utility bean
     */
    public static CmsJspVfsAccessBean create(CmsObject cms) {

        CmsJspVfsAccessBean result;
        Object attribute = cms.getRequestContext().getAttribute(ATTRIBUTE_VFS_ACCESS_BEAN);
        if (attribute != null) {
            result = (CmsJspVfsAccessBean)attribute;
        } else {
            result = new CmsJspVfsAccessBean(cms);
            cms.getRequestContext().setAttribute(ATTRIBUTE_VFS_ACCESS_BEAN, result);
        }
        return result;
    }

    /**
     * Returns the OpenCms user context this bean was initialized with.<p>
     * 
     * @return the OpenCms user context this bean was initialized with
     */
    public CmsObject getCmsObject() {

        return m_cms;
    }

    /**
     * Short form for {@link #getRequestContext()}.<p>
     * 
     * Usage example on a JSP with the EL:<pre>
     * The current URI is: ${cms:vfs(pageContext).context.uri}
     * </pre>
     * 
     * @return the OpenCms request context the current user this bean was initialized with
     *