001/*
002 * (C) Copyright 2006-2011 Nuxeo SA (http://nuxeo.com/) and others.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *     http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 *
016 * Contributors:
017 *     bstefanescu
018 *
019 * $Id$
020 */
021
022package org.nuxeo.ecm.platform.rendering.fm.extensions;
023
024import java.io.IOException;
025import java.io.Writer;
026import java.util.ArrayList;
027import java.util.List;
028
029import freemarker.template.TemplateException;
030
031/**
032 * @author <a href="mailto:[email protected]">Bogdan Stefanescu</a>
033 */
034public class BlockWriter extends Writer {
035
036    BlockWriterRegistry reg;
037
038    final String page;
039
040    final String name;
041
042    StringBuilder buf = new StringBuilder();
043
044    List<String> segments = new ArrayList<String>();
045
046    List<String> blocks = new ArrayList<String>();
047
048    BlockWriter superBlock; // the direct parent in the hierarchy - null if none
049
050    BlockWriter baseBlock; // the root of the block hierarchy - null if none
051
052    String ifBlockDefined;
053
054    // used to avoid writing blocks or characters in the current block writer.
055    // This is the case of the extension tag - that should ignore any content
056    // and blocks too because blocks inside extension tag
057    // must be derived blocks (the base hierarchy block will be found later when
058    // the extended base template will be parsed)
059    boolean suppressOutput = false;
060
061    public BlockWriter(String page, String name, BlockWriterRegistry reg) {
062        this.reg = reg;
063        this.name = name;
064        this.page = page;
065    }
066
067    public final BlockWriterRegistry getRegistry() {
068        return reg;
069    }
070
071    public void setSuppressOutput(boolean suppressOutput) {
072        this.suppressOutput = suppressOutput;
073    }
074
075    public boolean getSuppressOutput() {
076        return suppressOutput;
077    }
078
079    @Override
080    public void close() throws IOException {
081        buf = null;
082        segments = null;
083        blocks = null;
084        superBlock = null;
085        reg = null;
086    }
087
088    @Override
089    public void flush() throws IOException {
090        // do nothing
091    }
092
093    public boolean isEmpty() {
094        return buf.length() == 0 && segments.isEmpty() && blocks.isEmpty();
095    }
096
097    @Override
098    public void write(char[] cbuf, int off, int len) throws IOException {
099        if (!suppressOutput) {
100            buf.append(cbuf, off, len);
101        }
102    }
103
104    public void writeBlock(BlockWriter bw) {
105        if (!suppressOutput) {
106            // add the current buffer to the segments list
107            segments.add(buf.toString());
108            // reset buffer
109            buf.setLength(0);
110            // ad the sub block to the children block list
111            blocks.add(bw.name);
112        }
113        // inform the container about the new block
114        reg.addBlock(bw.name, bw);
115    }
116
117    public void writeSuperBlock() {
118        if (!suppressOutput) {
119            segments.add(buf.toString()); // add the current buffer to the
120            // segments list
121            buf.setLength(0); // reset buffer
122            blocks.add(".."); // add a special key that represent the super
123            // block
124        }
125    }
126
127    public void copyTo(Writer writer) throws TemplateException, IOException {
128        // check first if you need to suppress this block
129        if (ifBlockDefined != null) {
130            BlockWriter bw = reg.getBlock(ifBlockDefined);
131            if (bw == null || bw.isEmpty()) {
132                return;
133            }
134        }
135        for (int i = 0, len = segments.size(); i < len; i++) {
136            writer.write(segments.get(i));
137            String key = blocks.get(i);
138            BlockWriter bw = null;
139            if (key == "..") { // the super block
140                bw = superBlock;
141            } else { // a regular block
142                bw = reg.getBlock(key);
143            }
144            bw.copyTo(writer);
145        }
146        writer.write(buf.toString());
147    }
148
149    @Override
150    public String toString() {
151        return name + "@" + page;
152    }
153}