XMLOutputLister.java Source code

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Here is the source code for XMLOutputLister.java

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//   XMLOutputLister.java
//
//   The Kleene Programming Language

//   Copyright 2006-2012 SAP AG

//   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.

//   Author: ken.beesley@sap.com (Kenneth R. Beesley)

// Class that knows how to output Strings, via BufferedWriter, found in
// an Fst.  The challenge is that the Fst is in the C++ universe and is
// being searched by a native (C++) function.  That native function will
// be passed an object of type XMLOutputLister and will call back to
// methods of this object.
//
// This may seem roundabout, but it lets Java handle the Unicode I/O.
// And the symmap (needed to map ints to String) is on the Java side.

import java.util.Stack;
import java.util.Iterator;
import java.io.BufferedWriter;

//import org.apache.commons.lang.StringEscapeUtils ;

public class XMLOutputLister implements StringLister {

    private SymMap symmap;
    private Stack<Integer> intStack;
    private BufferedWriter bwriter;
    String outputElmtName;
    String weightAttrName;

    // Constructor
    public XMLOutputLister(SymMap sm, BufferedWriter bw, String oen, String wan) {
        symmap = sm;
        bwriter = bw;
        intStack = new Stack<Integer>();
        outputElmtName = oen;
        weightAttrName = wan;
    }

    // callback functions, called by the native C++ function finding 
    // strings in the Fst
    // output strings are built up integer by integer (codepoint by 
    // codepoint); the arcs
    // on the Fst just have integer labels

    public void push(int i) {
        intStack.push(new Integer(i));
    }

    public void pop() {
        intStack.pop();
    }

    public void emit(float w) {
        // get String from intStack (basically a list of label integers)
        StringBuilder sb = new StringBuilder();
        // iterate through the integers, convert to StringBuffer (UTF-16)
        for (Iterator<Integer> iter = intStack.iterator(); iter.hasNext();) {
            sb.append(symmap.getsym(iter.next().intValue()));
        }

        try {
            // StringEscapeUtils.escapeXml(str) escapes the five special
            //  XML characters, but also escapes all characters beyond
            //  the ASCII range
            bwriter.write("      <" + outputElmtName + " " + weightAttrName + "=\"" + w + "\">"
                    + EscapeXML.escapeXML(sb.toString()) + "</" + outputElmtName + ">");
            bwriter.newLine();
        } catch (Exception e) {
            // KRB:  what to do here?
            e.printStackTrace();
        }
    }
}