exobjlist.java

java 读写word excel ppt

/*
* 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.poi.hslf.record;

import java.io.IOException;
import java.io.OutputStream;
import java.util.ArrayList;

import org.apache.poi.util.LittleEndian;

/**
 * This class holds the links to exernal objects referenced
 *  from the document.
 * @author Nick Burch
 */
public class ExObjList extends RecordContainer {
	private byte[] _header;
	private static long _type = 1033;
	
	// Links to our more interesting children
	private ExObjListAtom exObjListAtom; 
	
	/** 
	 * Returns the ExObjListAtom of this list
	 */ 
	public ExObjListAtom getExObjListAtom() { return exObjListAtom; }
	
	/**
	 * Returns all the ExHyperlinks
	 */
	public ExHyperlink[] getExHyperlinks() {
		ArrayList links = new ArrayList();
		for(int i=0; i<_children.length; i++) {
			if(_children[i] instanceof ExHyperlink) {
				links.add(_children[i]);
			}
		}

		return (ExHyperlink[])links.toArray(new ExHyperlink[links.size()]);
	}

	/** 
	 * Set things up, and find our more interesting children
	 */
	protected ExObjList(byte[] source, int start, int len) {
		// Grab the header
		_header = new byte[8];
		System.arraycopy(source,start,_header,0,8);

		// Find our children
		_children = Record.findChildRecords(source,start+8,len-8);
		findInterestingChildren();
	}

	/**
	 * Go through our child records, picking out the ones that are
	 *  interesting, and saving those for use by the easy helper
	 *  methods.
	 */	
	private void findInterestingChildren() {
		// First child should be the atom
		if(_children[0] instanceof ExObjListAtom) {
			exObjListAtom = (ExObjListAtom)_children[0];
		} else {
			throw new IllegalStateException("First child record wasn't a ExObjListAtom, was of type " + _children[0].getRecordType());
		}
	}
	
	/**
	 * Create a new ExObjList, with blank fields
	 */
	public ExObjList() {
		_header = new byte[8];
		_children = new Record[1];
		
		// Setup our header block
		_header[0] = 0x0f; // We are a container record
		LittleEndian.putShort(_header, 2, (short)_type);
		
		// Setup our child records
		_children[0] = new ExObjListAtom();
		findInterestingChildren();
	}

	/**
	 * We are of type 1033
	 */
	public long getRecordType() { return _type; }

	/**
	 * Write the contents of the record back, so it can be written
	 *  to disk
	 */
	public void writeOut(OutputStream out) throws IOException {
		writeOut(_header[0],_header[1],_type,_children,out);
	}

    /**
     * Lookup a hyperlink by its unique id
     *
     * @param id hyperlink id
     * @return found <code>ExHyperlink</code> or <code>null</code>
     */
    public ExHyperlink get(int id){
        for(int i=0; i<_children.length; i++) {
            if(_children[i] instanceof ExHyperlink) {
                ExHyperlink rec = (ExHyperlink)_children[i];
                if (rec.getExHyperlinkAtom().getNumber() == id){
                    return rec;
                }
            }
        }
        return null;
    }
}