Java tutorial
/* * This program is free software; you can redistribute it and/or modify it under the * terms of the GNU Lesser General Public License, version 2.1 as published by the Free Software * Foundation. * * You should have received a copy of the GNU Lesser General Public License along with this * program; if not, you can obtain a copy at http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html * or from the Free Software Foundation, Inc., * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. * * This program 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. * * Copyright (c) 2006 - 2017 Hitachi Vantara and Contributors. All rights reserved. */ package org.pentaho.reporting.libraries.resourceloader.loader.file; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.pentaho.reporting.libraries.resourceloader.ResourceData; import org.pentaho.reporting.libraries.resourceloader.ResourceException; import org.pentaho.reporting.libraries.resourceloader.ResourceKey; import org.pentaho.reporting.libraries.resourceloader.ResourceKeyCreationException; import org.pentaho.reporting.libraries.resourceloader.ResourceKeyData; import org.pentaho.reporting.libraries.resourceloader.ResourceKeyUtils; import org.pentaho.reporting.libraries.resourceloader.ResourceLoader; import org.pentaho.reporting.libraries.resourceloader.ResourceLoadingException; import java.io.File; import java.io.FileNotFoundException; import java.io.IOException; import java.net.MalformedURLException; import java.net.URL; import java.util.HashMap; import java.util.Map; public class FileResourceLoader implements ResourceLoader { public static final String SCHEMA_NAME = FileResourceLoader.class.getName(); private static final Log logger = LogFactory.getLog(FileResourceLoader.class); public FileResourceLoader() { } /** * Checks, whether this resource loader implementation was responsible for creating this key. * * @param key * @return */ public boolean isSupportedKey(final ResourceKey key) { if (key == null) { throw new NullPointerException(); } if (SCHEMA_NAME.equals(key.getSchema())) { return true; } return false; } /** * Creates a new resource key from the given object and the factory keys. * * @param value * @param factoryKeys * @return the created key. * @throws org.pentaho.reporting.libraries.resourceloader.ResourceKeyCreationException if creating the key failed. */ public ResourceKey createKey(final Object value, final Map factoryKeys) throws ResourceKeyCreationException { if (value instanceof File) { final File f = (File) value; if (f.exists() && f.isFile()) { return new ResourceKey(SCHEMA_NAME, f, factoryKeys); } } else if (value instanceof String) { final File f = new File(String.valueOf(value)); if (f.exists() && f.isFile()) { return new ResourceKey(SCHEMA_NAME, f, factoryKeys); } } return null; } /** * Derives a new resource key from the given key. If neither a path nor new factory-keys are given, the parent key is * returned. * * @param parent the parent * @param path the derived path (can be null). * @param factoryKeys the optional factory keys (can be null). * @return the derived key. * @throws org.pentaho.reporting.libraries.resourceloader.ResourceKeyCreationException if the key cannot be derived * for any reason. */ public ResourceKey deriveKey(final ResourceKey parent, final String path, final Map factoryKeys) throws ResourceKeyCreationException { if (isSupportedKey(parent) == false) { throw new ResourceKeyCreationException("Assertation: Unsupported parent key type"); } try { final File target; if (path != null) { final File parentResource = (File) parent.getIdentifier(); final File parentFile = parentResource.getCanonicalFile().getParentFile(); if (parentFile == null) { throw new FileNotFoundException("Parent file does not exist"); } target = new File(parentFile, path); if (target.exists() == false || target.isFile() == false) { throw new ResourceKeyCreationException( "Malformed value: " + path + " (" + target + "): File does not exist."); } } else { target = (File) parent.getIdentifier(); } final Map map; if (factoryKeys != null) { map = new HashMap(); map.putAll(parent.getFactoryParameters()); map.putAll(factoryKeys); } else { map = parent.getFactoryParameters(); } return new ResourceKey(parent.getSchema(), target, map); } catch (IOException ioe) { throw new ResourceKeyCreationException("Failed to create key", ioe); } } public URL toURL(final ResourceKey key) { if (key == null) { throw new NullPointerException(); } if (isSupportedKey(key) == false) { throw new IllegalArgumentException("Key format is not recognized."); } try { final File file = (File) key.getIdentifier(); return file.toURI().toURL(); } catch (MalformedURLException e) { return null; } } public ResourceData load(final ResourceKey key) throws ResourceLoadingException { if (isSupportedKey(key) == false) { throw new ResourceLoadingException("Key format is not recognized."); } return new FileResourceData(key); } public String serialize(final ResourceKey bundleKey, final ResourceKey key) throws ResourceException { // Validate the parameter if (key == null) { throw new NullPointerException("The ResourceKey can not be null"); } if (isSupportedKey(key) == false) { throw new IllegalArgumentException("Key format is not recognized."); } if (!(key.getIdentifier() instanceof File)) { throw new IllegalArgumentException("ResourceKey is invalid - identifier is not a File object"); } // Log information logger.debug("Serializing a File Resource Key..."); if (key.getParent() != null) { throw new ResourceException( "Unable to serialize a File-ResourceKey with a parent. This type is not expected to have a parent."); } // Create a string version of the identifier try { final File file = (File) key.getIdentifier(); final String strIdentifier = file.getCanonicalPath(); final String result = ResourceKeyUtils.createStringResourceKey(key.getSchema().toString(), strIdentifier, key.getFactoryParameters()); logger.debug("Serialized File Resource Key: [" + result + "]"); return result; } catch (IOException ioe) { throw new IllegalArgumentException( "Could not determine cononical path to file specified in ResourceKey: " + ioe.getMessage()); } } public ResourceKey deserialize(final ResourceKey bundleKey, final String stringKey) throws ResourceKeyCreationException { // Parse the data final ResourceKeyData keyData = ResourceKeyUtils.parse(stringKey); // Validate the data if (SCHEMA_NAME.equals(keyData.getSchema()) == false) { throw new ResourceKeyCreationException("Serialized version of key does not contain correct schema"); } // Create a new file based on the path provided final File file = new File(keyData.getIdentifier()); return new ResourceKey(SCHEMA_NAME, file, keyData.getFactoryParameters()); } public boolean isSupportedDeserializer(final String data) { return SCHEMA_NAME.equals(ResourceKeyUtils.readSchemaFromString(data)); } }