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  /*
   * 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.jasper.tagplugins.jstl.core;
 
 
 public final class ForEach implements TagPlugin {
     
     private boolean hasVarhasBeginhasEndhasStep;
     
     public void doTag(TagPluginContext ctxt) {
         
         String index = null;
         
         boolean hasVarStatus = ctxt.isAttributeSpecified("varStatus");
         if (hasVarStatus) {
             ctxt.dontUseTagPlugin();
             return;
         }
         
          = ctxt.isAttributeSpecified("var");
          = ctxt.isAttributeSpecified("begin");
          = ctxt.isAttributeSpecified("end");
          = ctxt.isAttributeSpecified("step");
         
         boolean hasItems = ctxt.isAttributeSpecified("items");
         if (hasItems) {
             doCollection(ctxt);
             return;
         }
         
         // We must have a begin and end attributes
         index = ctxt.getTemporaryVariableName();
         ctxt.generateJavaSource("for (int " + index + " = ");
         ctxt.generateAttribute("begin");
         ctxt.generateJavaSource("; " + index + " <= ");
         ctxt.generateAttribute("end");
         if () {
             ctxt.generateJavaSource("; " + index + "+=");
             ctxt.generateAttribute("step");
             ctxt.generateJavaSource(") {");
         }
         else {
             ctxt.generateJavaSource("; " + index + "++) {");
         }
         
         // If var is specified and the body contains an EL, then sycn
         // the var attribute
         if ( /* && ctxt.hasEL() */) {
             ctxt.generateJavaSource("_jspx_page_context.setAttribute(");
             ctxt.generateAttribute("var");
             ctxt.generateJavaSource(", String.valueOf(" + index + "));");
         }
         ctxt.generateBody();
         ctxt.generateJavaSource("}");
     }
    
    
Generate codes for Collections The pseudo code is:
 
     private void doCollection(TagPluginContext ctxt) {
         
         ctxt.generateImport("java.util.*");
         generateIterators(ctxt);
         
         String itemsV = ctxt.getTemporaryVariableName();
         ctxt.generateJavaSource("Object " + itemsV + "= ");
         ctxt.generateAttribute("items");
         ctxt.generateJavaSource(";");
         
         String indexV=nullbeginV=nullendV=nullstepV=null;
         if () {
             beginV = ctxt.getTemporaryVariableName();
             ctxt.generateJavaSource("int " + beginV + " = ");
             ctxt.generateAttribute("begin");
             ctxt.generateJavaSource(";");
         }
         if () {
             indexV = ctxt.getTemporaryVariableName();
             ctxt.generateJavaSource("int " + indexV + " = 0;");
             endV = ctxt.getTemporaryVariableName();
             ctxt.generateJavaSource("int " + endV + " = ");
            ctxt.generateAttribute("end");
            ctxt.generateJavaSource(";");
        }
        if () {
            stepV = ctxt.getTemporaryVariableName();
            ctxt.generateJavaSource("int " + stepV + " = ");
            ctxt.generateAttribute("step");
            ctxt.generateJavaSource(";");
        }
        
        String iterV = ctxt.getTemporaryVariableName();
        ctxt.generateJavaSource("Iterator " + iterV + " = null;");
        // Object[]
        ctxt.generateJavaSource("if (" + itemsV + " instanceof Object[])");
        ctxt.generateJavaSource(iterV + "=toIterator((Object[])" + itemsV + ");");
        // boolean[]
        ctxt.generateJavaSource("else if (" + itemsV + " instanceof boolean[])");
        ctxt.generateJavaSource(iterV + "=toIterator((boolean[])" + itemsV + ");");
        // byte[]
        ctxt.generateJavaSource("else if (" + itemsV + " instanceof byte[])");
        ctxt.generateJavaSource(iterV + "=toIterator((byte[])" + itemsV + ");");
        // char[]
        ctxt.generateJavaSource("else if (" + itemsV + " instanceof char[])");
        ctxt.generateJavaSource(iterV + "=toIterator((char[])" + itemsV + ");");
        // short[]
        ctxt.generateJavaSource("else if (" + itemsV + " instanceof short[])");
        ctxt.generateJavaSource(iterV + "=toIterator((short[])" + itemsV + ");");
        // int[]
        ctxt.generateJavaSource("else if (" + itemsV + " instanceof int[])");
        ctxt.generateJavaSource(iterV + "=toIterator((int[])" + itemsV + ");");
        // long[]
        ctxt.generateJavaSource("else if (" + itemsV + " instanceof long[])");
        ctxt.generateJavaSource(iterV + "=toIterator((long[])" + itemsV + ");");
        // float[]
        ctxt.generateJavaSource("else if (" + itemsV + " instanceof float[])");
        ctxt.generateJavaSource(iterV + "=toIterator((float[])" + itemsV + ");");
        // double[]
        ctxt.generateJavaSource("else if (" + itemsV + " instanceof double[])");
        ctxt.generateJavaSource(iterV + "=toIterator((double[])" + itemsV + ");");
        
        // Collection
        ctxt.generateJavaSource("else if (" + itemsV + " instanceof Collection)");
        ctxt.generateJavaSource(iterV + "=((Collection)" + itemsV + ").iterator();");
        
        // Iterator
        ctxt.generateJavaSource("else if (" + itemsV + " instanceof Iterator)");
        ctxt.generateJavaSource(iterV + "=(Iterator)" + itemsV + ";");
        
        // Enumeration
        ctxt.generateJavaSource("else if (" + itemsV + " instanceof Enumeration)");
        ctxt.generateJavaSource(iterV + "=toIterator((Enumeration)" + itemsV + ");");
        
        // Map
        ctxt.generateJavaSource("else if (" + itemsV + " instanceof Map)");
        ctxt.generateJavaSource(iterV + "=((Map)" + itemsV + ").entrySet().iterator();");
        
        if () {
            String tV = ctxt.getTemporaryVariableName();
            ctxt.generateJavaSource("for (int " + tV + "=" + beginV + ";" +
                    tV + ">0 && " + iterV + ".hasNext(); " +
                    tV + "--)");
            ctxt.generateJavaSource(iterV + ".next();");
        }
        
        ctxt.generateJavaSource("while (" + iterV + ".hasNext()){");
        if () {
            ctxt.generateJavaSource("_jspx_page_context.setAttribute(");
            ctxt.generateAttribute("var");
            ctxt.generateJavaSource(", " + iterV + ".next());");
        }
        
        ctxt.generateBody();
        
        if () {
            String tV = ctxt.getTemporaryVariableName();
            ctxt.generateJavaSource("for (int " + tV + "=" + stepV + "-1;" +
                    tV + ">0 && " + iterV + ".hasNext(); " +
                    tV + "--)");
            ctxt.generateJavaSource(iterV + ".next();");
        }
        if () {
            if () {
                ctxt.generateJavaSource(indexV + "+=" + stepV + ";");
            }
            else {
                ctxt.generateJavaSource(indexV + "++;");
            }
            if () {
                ctxt.generateJavaSource("if(" + beginV + "+" + indexV +
                        ">"endV + ")");
            }
            else {
                ctxt.generateJavaSource("if(" + indexV + ">" + endV + ")");
            }
            ctxt.generateJavaSource("break;");
        }
        ctxt.generateJavaSource("}");	// while
    }
    
    
Generate iterators for data types supported in items
    private void generateIterators(TagPluginContext ctxt) {
        
        // Object[]
        ctxt.generateDeclaration("ObjectArrayIterator"
                "private Iterator toIterator(final Object[] a){\n" +
                "  return (new Iterator() {\n" +
                "    int index=0;\n" +
                "    public boolean hasNext() {\n" +
                "      return index < a.length;}\n" +
                "    public Object next() {\n" +
                "      return a[index++];}\n" +
                "    public void remove() {}\n" +
                "  });\n" +
                "}"
        );
        
        // boolean[]
        ctxt.generateDeclaration("booleanArrayIterator"
                "private Iterator toIterator(final boolean[] a){\n" +
                "  return (new Iterator() {\n" +
                "    int index=0;\n" +
                "    public boolean hasNext() {\n" +
                "      return index < a.length;}\n" +
                "    public Object next() {\n" +
                "      return new Boolean(a[index++]);}\n" +
                "    public void remove() {}\n" +
                "  });\n" +
                "}"
        );
        
        // byte[]
        ctxt.generateDeclaration("byteArrayIterator"
                "private Iterator toIterator(final byte[] a){\n" +
                "  return (new Iterator() {\n" +
                "    int index=0;\n" +
                "    public boolean hasNext() {\n" +
                "      return index < a.length;}\n" +
                "    public Object next() {\n" +
                "      return new Byte(a[index++]);}\n" +
                "    public void remove() {}\n" +
                "  });\n" +
                "}"
        );
        
        // char[]
        ctxt.generateDeclaration("charArrayIterator"
                "private Iterator toIterator(final char[] a){\n" +
                "  return (new Iterator() {\n" +
                "    int index=0;\n" +
                "    public boolean hasNext() {\n" +
                "      return index < a.length;}\n" +
                "    public Object next() {\n" +
                "      return new Character(a[index++]);}\n" +
                "    public void remove() {}\n" +
                "  });\n" +
                "}"
        );
        
        // short[]
        ctxt.generateDeclaration("shortArrayIterator"
                "private Iterator toIterator(final short[] a){\n" +
                "  return (new Iterator() {\n" +
                "    int index=0;\n" +
                "    public boolean hasNext() {\n" +
                "      return index < a.length;}\n" +
                "    public Object next() {\n" +
                "      return new Short(a[index++]);}\n" +
                "    public void remove() {}\n" +
                "  });\n" +
                "}"
        );
        
        // int[]
        ctxt.generateDeclaration("intArrayIterator"
                "private Iterator toIterator(final int[] a){\n" +
                "  return (new Iterator() {\n" +
                "    int index=0;\n" +
                "    public boolean hasNext() {\n" +
                "      return index < a.length;}\n" +
                "    public Object next() {\n" +
                "      return new Integer(a[index++]);}\n" +
                "    public void remove() {}\n" +
                "  });\n" +
                "}"
        );
        
        // long[]
        ctxt.generateDeclaration("longArrayIterator"
                "private Iterator toIterator(final long[] a){\n" +
                "  return (new Iterator() {\n" +
                "    int index=0;\n" +
                "    public boolean hasNext() {\n" +
                "      return index < a.length;}\n" +
                "    public Object next() {\n" +
                "      return new Long(a[index++]);}\n" +
                "    public void remove() {}\n" +
                "  });\n" +
                "}"
        );
        
        // float[]
        ctxt.generateDeclaration("floatArrayIterator",
                "private Iterator toIterator(final float[] a){\n" +
                "  return (new Iterator() {\n" +
                "    int index=0;\n" +
                "    public boolean hasNext() {\n" +
                "      return index < a.length;}\n" +
                "    public Object next() {\n" +
                "      return new Float(a[index++]);}\n" +
                "    public void remove() {}\n" +
                "  });\n" +
                "}"
        );
        
        // double[]
        ctxt.generateDeclaration("doubleArrayIterator",
                "private Iterator toIterator(final double[] a){\n" +
                "  return (new Iterator() {\n" +
                "    int index=0;\n" +
                "    public boolean hasNext() {\n" +
                "      return index < a.length;}\n" +
                "    public Object next() {\n" +
                "      return new Double(a[index++]);}\n" +
                "    public void remove() {}\n" +
                "  });\n" +
                "}"
        );
        
        // Enumeration
        ctxt.generateDeclaration("enumIterator",
                "private Iterator toIterator(final Enumeration e){\n" +
                "  return (new Iterator() {\n" +
                "    public boolean hasNext() {\n" +
                "      return e.hasMoreElements();}\n" +
                "    public Object next() {\n" +
                "      return e.nextElement();}\n" +
                "    public void remove() {}\n" +
                "  });\n" +
                "}"
        );
        
    }
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