Java tutorial
/* * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You 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 org.apache.pdflens.views.treeview; /** * A tree model that uses a cos document. * * * @author wurtz * @author <a href="mailto:ben@benlitchfield.com">Ben Litchfield</a> * @version $Revision: 1.9 $ */ import javax.swing.tree.TreePath; import javax.swing.tree.TreeModel; //import java.awt.event.*; import javax.swing.event.TreeModelListener; import org.apache.pdfbox.cos.COSArray; import org.apache.pdfbox.cos.COSBase; import org.apache.pdfbox.cos.COSDictionary; import org.apache.pdfbox.cos.COSDocument; import org.apache.pdfbox.cos.COSName; import org.apache.pdfbox.cos.COSObject; import org.apache.pdfbox.pdmodel.PDDocument; import java.util.ArrayList; import java.util.Collections; import java.util.List; /** * A class to model a PDF document as a tree structure. * * @author <a href="mailto:ben@benlitchfield.com">Ben Litchfield</a> * @version $Revision: 1.9 $ */ class PDFTreeModel implements TreeModel { private PDDocument document; /** * constructor. */ public PDFTreeModel() { //default constructor } /** * Constructor to take a document. * * @param doc The document to display in the tree. */ public PDFTreeModel(PDDocument doc) { setDocument(doc); } /** * Set the document to display in the tree. * * @param doc The document to display in the tree. */ public void setDocument(PDDocument doc) { document = doc; } /** * Adds a listener for the <code>TreeModelEvent</code> * posted after the tree changes. * * @param l the listener to add * @see #removeTreeModelListener * */ public void addTreeModelListener(TreeModelListener l) { //required for interface } /** * Returns the child of <code>parent</code> at index <code>index</code> * in the parent's * child array. <code>parent</code> must be a node previously obtained * from this data source. This should not return <code>null</code> * if <code>index</code> * is a valid index for <code>parent</code> (that is <code>index >= 0 && * index < getChildCount(parent</code>)). * * @param parent a node in the tree, obtained from this data source * @param index The index into the parent object to location the child object. * @return the child of <code>parent</code> at index <code>index</code> * */ public Object getChild(Object parent, int index) { Object retval = null; if (parent instanceof COSArray) { ArrayEntry entry = new ArrayEntry(); entry.setIndex(index); entry.setValue(((COSArray) parent).getObject(index)); retval = entry; } else if (parent instanceof COSDictionary) { COSDictionary dict = ((COSDictionary) parent); List<COSName> keys = new ArrayList<COSName>(dict.keySet()); Collections.sort(keys); Object key = keys.get(index); Object value = dict.getDictionaryObject((COSName) key); MapEntry entry = new MapEntry(); entry.setKey(key); entry.setValue(value); retval = entry; } else if (parent instanceof MapEntry) { retval = getChild(((MapEntry) parent).getValue(), index); } else if (parent instanceof ArrayEntry) { retval = getChild(((ArrayEntry) parent).getValue(), index); } else if (parent instanceof COSDocument) { retval = ((COSDocument) parent).getObjects().get(index); } else if (parent instanceof COSObject) { retval = ((COSObject) parent).getObject(); } else { throw new RuntimeException("Unknown COS type " + parent.getClass().getName()); } return retval; } /** Returns the number of children of <code>parent</code>. * Returns 0 if the node * is a leaf or if it has no children. <code>parent</code> must be a node * previously obtained from this data source. * * @param parent a node in the tree, obtained from this data source * @return the number of children of the node <code>parent</code> * */ public int getChildCount(Object parent) { int retval = 0; if (parent instanceof COSArray) { retval = ((COSArray) parent).size(); } else if (parent instanceof COSDictionary) { retval = ((COSDictionary) parent).size(); } else if (parent instanceof MapEntry) { retval = getChildCount(((MapEntry) parent).getValue()); } else if (parent instanceof ArrayEntry) { retval = getChildCount(((ArrayEntry) parent).getValue()); } else if (parent instanceof COSDocument) { retval = ((COSDocument) parent).getObjects().size(); } else if (parent instanceof COSObject) { retval = 1; } return retval; } /** Returns the index of child in parent. If <code>parent</code> * is <code>null</code> or <code>child</code> is <code>null</code>, * returns -1. * * @param parent a note in the tree, obtained from this data source * @param child the node we are interested in * @return the index of the child in the parent, or -1 if either * <code>child</code> or <code>parent</code> are <code>null</code> * */ public int getIndexOfChild(Object parent, Object child) { int retval = -1; if (parent != null && child != null) { if (parent instanceof COSArray) { COSArray array = (COSArray) parent; if (child instanceof ArrayEntry) { ArrayEntry arrayEntry = (ArrayEntry) child; retval = arrayEntry.getIndex(); } else { retval = array.indexOf((COSBase) child); } } else if (parent instanceof COSDictionary) { MapEntry entry = (MapEntry) child; COSDictionary dict = (COSDictionary) parent; List<COSName> keys = new ArrayList<COSName>(dict.keySet()); Collections.sort(keys); for (int i = 0; retval == -1 && i < keys.size(); i++) { if (keys.get(i).equals(entry.getKey())) { retval = i; } } } else if (parent instanceof MapEntry) { retval = getIndexOfChild(((MapEntry) parent).getValue(), child); } else if (parent instanceof ArrayEntry) { retval = getIndexOfChild(((ArrayEntry) parent).getValue(), child); } else if (parent instanceof COSDocument) { retval = ((COSDocument) parent).getObjects().indexOf(child); } else if (parent instanceof COSObject) { retval = 0; } else { throw new RuntimeException("Unknown COS type " + parent.getClass().getName()); } } return retval; } /** Returns the root of the tree. Returns <code>null</code> * only if the tree has no nodes. * * @return the root of the tree * */ public Object getRoot() { //return document.getDocument().getTrailer(); return document.getDocument(); } /** Returns <code>true</code> if <code>node</code> is a leaf. * It is possible for this method to return <code>false</code> * even if <code>node</code> has no children. * A directory in a filesystem, for example, * may contain no files; the node representing * the directory is not a leaf, but it also has no children. * * @param node a node in the tree, obtained from this data source * @return true if <code>node</code> is a leaf * */ public boolean isLeaf(Object node) { boolean isLeaf = !(node instanceof COSDictionary || node instanceof COSArray || node instanceof COSDocument || node instanceof COSObject || (node instanceof MapEntry && !isLeaf(((MapEntry) node).getValue())) || (node instanceof ArrayEntry && !isLeaf(((ArrayEntry) node).getValue()))); return isLeaf; } /** Removes a listener previously added with * <code>addTreeModelListener</code>. * * @see #addTreeModelListener * @param l the listener to remove * */ public void removeTreeModelListener(TreeModelListener l) { //required for interface } /** Messaged when the user has altered the value for the item identified * by <code>path</code> to <code>newValue</code>. * If <code>newValue</code> signifies a truly new value * the model should post a <code>treeNodesChanged</code> event. * * @param path path to the node that the user has altered * @param newValue the new value from the TreeCellEditor * */ public void valueForPathChanged(TreePath path, Object newValue) { //required for interface } }