iteratecontext.java

本套系统采用了业界当前最为流行的beanAction组件

/*
 * Created on Apr 17, 2005
 *
 */
package com.ibatis.sqlmap.engine.mapping.sql.dynamic.elements;

import java.lang.reflect.Array;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

import com.ibatis.sqlmap.client.SqlMapException;

/**
 * @author Brandon Goodin
 */
public class IterateContext implements Iterator {
  
  private static final String PROCESS_INDEX = "ProcessIndex";
  private static final String PROCESS_STRING = "ProcessString";
  
  private Iterator iterator;
  private int index = -1;

  private String property;
  private boolean allowNext = true;

  private boolean isFinal = false;
  private SqlTag tag;
  
  private IterateContext parent;
  
  /**
   * This variable is true if some of the sub elements have
   * actually produced content.  This is used to test
   * whether to add the open and conjunction text to the
   * generated statement.
   * 
   * This variable is used to replace the deprecated and dangerous
   * isFirst method.
   */
  private boolean someSubElementsHaveContent;
  
  /**
   * This variable is set by the doEndFragment method in IterateTagHandler
   * to specify that the first content producing sub element has happened.
   * The doPrepend method will test the value to know whether or not
   * to process the prepend.
   * 
   * This variable is used to replace the deprecated and dangerous
   * isFirst method.
   */
  private boolean isPrependEnabled;
  
  public IterateContext(Object collection,SqlTag tag, IterateContext parent) {
    this.parent = parent;
    this.tag = tag;
    if (collection instanceof Collection) {
      this.iterator = ((Collection) collection).iterator();
    } else if (collection instanceof Iterator) {
      this.iterator = ((Iterator) collection);
    } else if (collection.getClass().isArray()) {
      List list = arrayToList(collection);
      this.iterator = list.iterator();
    } else {
      throw new SqlMapException("ParameterObject or property was not a Collection, Array or Iterator.");
    }
  }

  public boolean hasNext() {
    return iterator != null && iterator.hasNext();
  }

  public Object next() {
    index++;
    return iterator.next();
  }

  public void remove() {
    iterator.remove();
  }

  public int getIndex() {
    return index;
  }

  /**
   * 
   * @return
   * @deprecated This method should not be used to decide whether or not to
   * add prepend and open text to the generated statement.  Rather, use the
   * methods isPrependEnabled() and someSubElementsHaveContent().
   */
  public boolean isFirst() {
    return index == 0;
  }

  public boolean isLast() {
    return iterator != null && !iterator.hasNext();
  }
  
  private List arrayToList(Object array) {
    List list = null;
    if (array instanceof Object[]) {
      list = Arrays.asList((Object[]) array);
    } else {
      list = new ArrayList();
      for (int i = 0, n = Array.getLength(array); i < n; i++) {
        list.add(Array.get(array, i));
      }
    }
    return list;
  }

  /**
   * @return Returns the property.
   */
  public String getProperty() {
    return property;
  }
  
  /**
   * This property specifies whether to increment the iterate in
   * the doEndFragment. The ConditionalTagHandler has the ability
   * to increment the IterateContext, so it is neccessary to avoid
   * incrementing in both the ConditionalTag and the IterateTag.
   *
   * @param property The property to set.
   */
  public void setProperty(String property) {
    this.property = property;
  }
  
  /**
   * @return Returns the allowNext.
   */
  public boolean isAllowNext() {
    return allowNext;
  }
  
  /**
   * @param performIterate The allowNext to set.
   */
  public void setAllowNext(boolean performIterate) {
    this.allowNext = performIterate;
  }
  /**
   * @return Returns the tag.
   */
  public SqlTag getTag() {
    return tag;
  }
  /**
   * @param tag The tag to set.
   */
  public void setTag(SqlTag tag) {
    this.tag = tag;
  }

  /**
   *
   * @return
   */
  public boolean isFinal() {
    return isFinal;
  }

  /**
   * This attribute is used to mark whether an iterate tag is
   * in it's final iteration. Since the ConditionalTagHandler
   * can increment the iterate the final iterate in the doEndFragment
   * of the IterateTagHandler needs to know it is in it's final iterate.
   *
   * @param aFinal
   */
  public void setFinal(boolean aFinal) {
    isFinal = aFinal;
  }
  
  
  /**
   * Returns the last property of any bean specified in this IterateContext.
   * @return The last property of any bean specified in this IterateContext.
   */
  public String getEndProperty() {
      if (parent != null) {
          int parentPropertyIndex = property.indexOf(parent.getProperty());
          if (parentPropertyIndex > -1) {
              int endPropertyIndex1 = property.indexOf(']', parentPropertyIndex);
              int endPropertyIndex2 = property.indexOf('.', parentPropertyIndex);
              return property.substring(parentPropertyIndex + Math.max(endPropertyIndex1, endPropertyIndex2) + 1, property.length());
          }
          else {
              return property;
          }
      }
      else {
          return property;
      }
  }
  
  /**
   * Replaces value of a tag property to match it's value with current iteration and all other iterations.
   * @param tagProperty the property of a TagHandler.
   * @return A Map containing the modified tag property in PROCESS_STRING key and the index where the modification occured in PROCESS_INDEX key.
   */
  protected Map processTagProperty(String tagProperty) {
      if (parent != null) {
          Map parentResult = parent.processTagProperty(tagProperty);
          return this.addIndex((String) parentResult.get(PROCESS_STRING), ((Integer) parentResult.get(PROCESS_INDEX)).intValue());
      }
      else {
          return this.addIndex(tagProperty, 0);
      }
  }
  
  /**
   * Replaces value of a tag property to match it's value with current iteration and all other iterations.
   * @param tagProperty the property of a TagHandler.
   * @return The tag property with all "[]" replaced with the correct iteration value.
   */
  public String addIndexToTagProperty(String tagProperty) {
      Map map = this.processTagProperty(tagProperty);
      return (String) map.get(PROCESS_STRING);
  }
  
  /**
   * Adds index value to the first found property matching this Iteration starting at index startIndex.
   * @param input The input String.
   * @param startIndex The index where search for property begins.
   * @return A Map containing the modified tag property in PROCESS_STRING key and the index where the modification occured in PROCESS_INDEX key.
   */
  protected Map addIndex(String input, int startIndex) {
      String endProperty = getEndProperty() + "[";
      int propertyIndex = input.indexOf(endProperty, startIndex);
      int modificationIndex = 0;
      // Is the iterate property in the tag property at all?
      if (propertyIndex > -1) {
          // Make sure the tag property does not already have a number.
          if (input.charAt(propertyIndex + endProperty.length()) == ']') {
              // Add iteration number to property.
              input = input.substring(0, propertyIndex + endProperty.length()) + this.getIndex() + input.substring(propertyIndex + endProperty.length());
              modificationIndex = propertyIndex + endProperty.length();
          }
      }
      Map ret = new HashMap();
      ret.put(PROCESS_INDEX, new Integer(modificationIndex));
      ret.put(PROCESS_STRING, input);
      return ret;
  }
  
  
  public IterateContext getParent() {
    return parent;
  }

  public void setParent(IterateContext parent) {
    this.parent = parent;
  }

  public boolean someSubElementsHaveContent() {
    return someSubElementsHaveContent;
  }

  public void setSomeSubElementsHaveContent(boolean someSubElementsHaveContent) {
    this.someSubElementsHaveContent = someSubElementsHaveContent;
  }

  public boolean isPrependEnabled() {
    return isPrependEnabled;
  }

  public void setPrependEnabled(boolean isPrependEnabled) {
    this.isPrependEnabled = isPrependEnabled;
  }
}