content: /*
   *  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
   *
   *      https://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.tools.ant.types.resources.selectors;
  
  import java.util.Stack;
  
  import org.apache.tools.ant.BuildException;
  import org.apache.tools.ant.Project;
  import org.apache.tools.ant.types.Comparison;
  import org.apache.tools.ant.types.DataType;
  import org.apache.tools.ant.types.Quantifier;
  import org.apache.tools.ant.types.Resource;
  import org.apache.tools.ant.types.ResourceCollection;
  import org.apache.tools.ant.types.resources.Union;
  import org.apache.tools.ant.types.resources.comparators.DelegatedResourceComparator;
  import org.apache.tools.ant.types.resources.comparators.ResourceComparator;
  
  /**
   * ResourceSelector that compares against "control" Resource(s)
   * using ResourceComparators.
   * @since Ant 1.7
   */
  public class Compare extends DataType implements ResourceSelector {
  
      private DelegatedResourceComparator comp = new DelegatedResourceComparator();
      private Quantifier against = Quantifier.ALL;
  
      private Comparison when = Comparison.EQUAL;
  
      private Union control;
  
      /**
       * Add a ResourceComparator to this Compare selector.
       * If multiple ResourceComparators are added, they will be processed in LIFO order.
       * @param c the ResourceComparator to add.
       */
      public synchronized void add(ResourceComparator c) {
          if (isReference()) {
              throw noChildrenAllowed();
          }
          comp.add(c);
          setChecked(false);
      }
  
      /**
       * Set the quantifier to be used. Default "all".
       * @param against the Quantifier EnumeratedAttribute to use.
       */
      public synchronized void setAgainst(Quantifier against) {
          if (isReference()) {
              throw tooManyAttributes();
          }
          this.against = against;
      }
  
      /**
       * Set the comparison to be used. Default "equal".
       * @param when the Comparison EnumeratedAttribute to use.
       */
      public synchronized void setWhen(Comparison when) {
          if (isReference()) {
              throw tooManyAttributes();
          }
          this.when = when;
      }
  
      /**
       * Create the nested control element. These are the
       * resources to compare against.
       * @return ResourceCollection.
       */
      public synchronized ResourceCollection createControl() {
          if (isReference()) {
              throw noChildrenAllowed();
          }
          if (control != null) {
              throw oneControl();
          }
          control = new Union();
          setChecked(false);
          return control;
      }
  
      //implement ResourceSelector; inherit doc
      /** {@inheritDoc} */
      public synchronized boolean isSelected(Resource r) {
          if (isReference()) {
              return getRef().isSelected(r);
          }
          if (control == null) {
              throw oneControl();
          }
          dieOnCircularReference();
          int t = 0, f = 0;
          for (Resource res : control) {
              if (when.evaluate(comp.compare(r, res))) {
                  t++;
              } else {
                  f++;
              }
          }
          return against.evaluate(t, f);
      }
  
      /**
       * Overrides the version from DataType
       * to recurse on nested ResourceComparators.
       * @param stk the stack of data types to use (recursively).
       * @param p   the project to use to dereference the references.
       * @throws BuildException on error.
       */
      protected synchronized void dieOnCircularReference(Stack<Object> stk, Project p)
          throws BuildException {
          if (isChecked()) {
              return;
          }
          if (isReference()) {
              super.dieOnCircularReference(stk, p);
          } else {
              if (control != null) {
                  DataType.pushAndInvokeCircularReferenceCheck(control, stk, p);
              }
              DataType.pushAndInvokeCircularReferenceCheck(comp, stk, p);
              setChecked(true);
          }
      }
  
      private ResourceSelector getRef() {
          return getCheckedRef(ResourceSelector.class);
      }
  
      private BuildException oneControl() {
          return new BuildException("%s the <control> element should be specified exactly once.",
                  super.toString());
      }
  }
  