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/**
 * Copyright (C) 2006-2014 phloc systems
 * http://www.phloc.com
 * office[at]phloc[dot]com
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *         http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.phloc.commons.microdom.reader;

import java.io.InputStream;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;

import javax.annotation.Nonnull;
import javax.annotation.Nullable;
import javax.annotation.WillClose;
import javax.annotation.concurrent.Immutable;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.phloc.commons.ValueEnforcer;
import com.phloc.commons.annotations.PresentForCodeCoverage;
import com.phloc.commons.annotations.ReturnsMutableCopy;
import com.phloc.commons.io.EAppend;
import com.phloc.commons.io.IInputStreamProvider;
import com.phloc.commons.io.IOutputStreamProvider;
import com.phloc.commons.io.streams.StreamUtils;
import com.phloc.commons.microdom.IMicroDocument;
import com.phloc.commons.microdom.IMicroElement;
import com.phloc.commons.microdom.impl.MicroDocument;
import com.phloc.commons.microdom.serialize.MicroReader;
import com.phloc.commons.microdom.serialize.MicroWriter;
import com.phloc.commons.state.ESuccess;
import com.phloc.commons.xml.serialize.XMLWriterSettings;

/**
 * Simple class that reads a list from an XML input stream.
* The XML file needs to look as follows: * *
 * <list>
 *   <item value="..."/>
 *   <item value="..."/>
 *   ...
 * </list>
 * 
* * @author Philip Helger */ @Immutable public final class XMLListHandler { /** Name of the root element */ public static final String ELEMENT_LIST = "list"; /** Element name of a single item */ public static final String ELEMENT_ITEM = "item"; /** Attribute name for the item value */ public static final String ATTR_VALUE = "value"; private static final Logger s_aLogger = LoggerFactory.getLogger (XMLListHandler.class); @PresentForCodeCoverage @SuppressWarnings ("unused") private static final XMLListHandler s_aInstance = new XMLListHandler (); private XMLListHandler () {} @Nullable @ReturnsMutableCopy public static List readList (@Nonnull final IInputStreamProvider aISP) { ValueEnforcer.notNull (aISP, "InputStreamProvider"); return readList (aISP.getInputStream ()); } @Nonnull public static ESuccess readList (@Nonnull final IInputStreamProvider aISP, @Nonnull final Collection aTargetList) { ValueEnforcer.notNull (aISP, "InputStreamProvider"); return readList (aISP.getInputStream (), aTargetList); } /** * Read a predefined XML file that contains list items. * * @param aIS * The input stream to read from. May not be null. * Automatically closed no matter whether reading succeeded or not. * @return null if reading fails - all list items otherwise. */ @Nullable @ReturnsMutableCopy public static List readList (@Nonnull @WillClose final InputStream aIS) { final List ret = new ArrayList (); if (readList (aIS, ret).isFailure ()) return null; return ret; } /** * Read a predefined XML file that contains list items. * * @param aIS * The input stream to read from. May not be null. * Automatically closed no matter whether reading succeeded or not. * @param aTargetList * The target collection to be filled. May not be null. * @return {@link ESuccess#SUCCESS} if reading succeeded, * {@link ESuccess#FAILURE} if the input stream is no valid XML or any * other error occurred. */ @Nonnull public static ESuccess readList (@Nonnull @WillClose final InputStream aIS, @Nonnull final Collection aTargetList) { ValueEnforcer.notNull (aIS, "InputStream"); ValueEnforcer.notNull (aTargetList, "TargetList"); try { // open file final IMicroDocument aDoc = MicroReader.readMicroXML (aIS); if (aDoc != null) { readList (aDoc.getDocumentElement (), aTargetList); return ESuccess.SUCCESS; } } catch (final Throwable t) { s_aLogger.warn ("Failed to read list resource '" + aIS + "'", t); } finally { StreamUtils.close (aIS); } return ESuccess.FAILURE; } @Nonnull public static ESuccess readList (@Nonnull final IMicroElement aParentElement, @Nonnull final Collection aTargetList) { ValueEnforcer.notNull (aParentElement, "ParentElement"); ValueEnforcer.notNull (aTargetList, "TargetList"); try { // and insert all elements for (final IMicroElement eItem : aParentElement.getAllChildElements (ELEMENT_ITEM)) { final String sValue = eItem.getAttribute (ATTR_VALUE); if (sValue == null) s_aLogger.warn ("Ignoring list item because value is null"); else if (!aTargetList.add (sValue)) s_aLogger.warn ("Ignoring list item '" + sValue + "' because value is already contained"); } return ESuccess.SUCCESS; } catch (final Throwable t) { s_aLogger.warn ("Failed to read list document", t); } return ESuccess.FAILURE; } @Nonnull public static IMicroDocument createListDocument (@Nonnull final Collection aCollection) { ValueEnforcer.notNull (aCollection, "Collection"); final IMicroDocument aDoc = new MicroDocument (); final IMicroElement eRoot = aDoc.appendElement (ELEMENT_LIST); for (final String sItem : aCollection) { final IMicroElement eItem = eRoot.appendElement (ELEMENT_ITEM); eItem.setAttribute (ATTR_VALUE, sItem); } return aDoc; } @Nonnull public static ESuccess writeList (@Nonnull final Collection aCollection, @Nonnull final IOutputStreamProvider aOSP) { ValueEnforcer.notNull (aOSP, "OutputStreamProvider"); return writeList (aCollection, aOSP.getOutputStream (EAppend.DEFAULT)); } /** * Write the passed collection to the passed output stream using the * predefined XML layout. * * @param aCollection * The map to be written. May not be null. * @param aOS * The output stream to write to. The stream is closed independent of * success or failure. May not be null. * @return {@link ESuccess#SUCCESS} when everything went well, * {@link ESuccess#FAILURE} otherwise. */ @Nonnull public static ESuccess writeList (@Nonnull final Collection aCollection, @Nonnull @WillClose final OutputStream aOS) { ValueEnforcer.notNull (aCollection, "Collection"); ValueEnforcer.notNull (aOS, "OutputStream"); try { final IMicroDocument aDoc = createListDocument (aCollection); return MicroWriter.writeToStream (aDoc, aOS, XMLWriterSettings.DEFAULT_XML_SETTINGS); } finally { StreamUtils.close (aOS); } } }




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