Add the <first> resource collection, plus its parent,

BaseResourceCollectionWrapper.


git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@278491 13f79535-47bb-0310-9956-ffa450edef68

docs/manual/CoreTypes/resources.html

@@ -222,6 +222,8 @@ Ant's "legacy" datatypes have been modified to behave as Resource Collections:
   <li><a href="#restrict">restrict</a> - restrict a resource collection
     to include only resources meeting specified criteria</li>
   <li><a href="#sort">sort</a> - sorted resource collection</li>
+  <li><a href="#first">first</a> - first <i>n</i> resources from a
+    nested collection</li>
   <li><a href="#union">union</a> - set union of nested resource collections</li>
   <li><a href="#intersect">intersect</a> - set intersection
     of nested resource collections</li>
@@ -514,6 +516,19 @@ platforms.
 <p>Sorts another nested resource collection according to the resources'
 natural order, or by one or more nested resource comparators:</p>
 <blockquote>
+  <table border="1" cellpadding="2" cellspacing="0">
+    <tr>
+      <td valign="top"><b>Attribute</b></td>
+      <td valign="top"><b>Description</b></td>
+      <td align="center" valign="top"><b>Required</b></td>
+    </tr>
+    <tr>
+      <td valign="top">cache</td>
+      <td valign="top">Whether to cache results; disabling
+        may seriously impact performance</td>
+      <td valign="top" align="center">No, default <i>true</i></td>
+    </tr>
+  </table>
   <h4>Parameters specified as nested elements</h4>
   <p>A single resource collection is required.</p>
   <p>The sort can be controlled and customized by specifying one or more
@@ -532,7 +547,7 @@ natural order, or by one or more nested resource comparators:</p>
     <li><a href="#rcmp.size">size</a> - sort resources by size</li>
     <li><a href="#rcmp.content">content</a> - sort resources by content</li>
     <li><a href="#rcmp.reverse">reverse</a> - reverse the natural sort order,
-      or a single nested resource comparator</li>
+      or that of a single nested resource comparator</li>
   </ul>
 
   <h4><a name="rcmp.name">name</a></h4>
@@ -570,10 +585,38 @@ natural order, or by one or more nested resource comparators:</p>
   </table>
 
   <h4><a name="rcmp.reverse">reverse</a></h4>
-  <p>Reverse the natural sort order, or a single nested comparator.</p>
+  <p>Reverse the natural sort order, or that of a single nested comparator.</p>
 
 </blockquote>
 
+<h4><a name="first">first</a></h4>
+<p>Includes the first <i>count</i> resources from a nested resource collection.
+This can be used in conjunction with the <a href="#sort">sort</a> collection,
+for example, to select the first few oldest, largest, etc. resources from a
+larger collection.</p>
+<blockquote>
+  <table border="1" cellpadding="2" cellspacing="0">
+    <tr>
+      <td valign="top"><b>Attribute</b></td>
+      <td valign="top"><b>Description</b></td>
+      <td align="center" valign="top"><b>Required</b></td>
+    </tr>
+    <tr>
+      <td valign="top">count</td>
+      <td valign="top">The number of resources to include</td>
+      <td valign="top" align="center">No, default 1</td>
+    </tr>
+    <tr>
+      <td valign="top">cache</td>
+      <td valign="top">Whether to cache results; disabling
+        may seriously impact performance</td>
+      <td valign="top" align="center">No, default <i>true</i></td>
+    </tr>
+  </table>
+  <h4>Parameters specified as nested elements</h4>
+  <p>A single resource collection is required.</p>
+</blockquote>
+
 <h4><a name="setlogic">Set operations</a></h4>
 <blockquote>
   <p>The following resource collections implement set operations:</p>
@@ -592,6 +635,21 @@ natural order, or by one or more nested resource comparators:</p>
   <h4><a name="difference">difference</a></h4>
   <p>Difference of nested resource collections.</p>
 
+  <p>The following attributes apply to all set-operation resource collections:
+  </p>
+  <table border="1" cellpadding="2" cellspacing="0">
+    <tr>
+      <td valign="top"><b>Attribute</b></td>
+      <td valign="top"><b>Description</b></td>
+      <td align="center" valign="top"><b>Required</b></td>
+    </tr>
+    <tr>
+      <td valign="top">cache</td>
+      <td valign="top">Whether to cache results; disabling
+        may seriously impact performance</td>
+      <td valign="top" align="center">No, default <i>true</i></td>
+    </tr>
+  </table>
 </blockquote>
 
 <hr>
@@ -599,4 +657,4 @@ natural order, or by one or more nested resource comparators:</p>
 Reserved.</p>
 
 </body>
-</html>
+</html>

src/etc/testcases/types/resources/build.xml

@@ -445,6 +445,50 @@ depends="testfileurl,testfileurlref,testhttpurl1,testhttpurl2,testjarurl,testres
   <target name="single"
     depends="testresource,url,testfile,string,testzipentry,testproperty" />
 
-  <target name="all" depends="legacy,files,resources,setlogic,single" />
+  <target name="testfirst0">
+    <fail>
+      <condition>
+        <not>
+          <resourcecount count="0">
+            <first count="0">
+              <filelist dir="${dir}" files="1,2,3,4,5" />
+            </first>
+          </resourcecount>
+        </not>
+      </condition>
+    </fail>
+  </target>
+
+  <target name="testfirst1">
+    <fail>
+      <condition>
+        <not>
+          <resourcecount count="1">
+            <first>
+              <filelist dir="${dir}" files="1,2,3,4,5" />
+            </first>
+          </resourcecount>
+        </not>
+      </condition>
+    </fail>
+  </target>
+
+  <target name="testfirst2">
+    <fail>
+      <condition>
+        <not>
+          <resourcecount count="2">
+            <first count="2">
+              <filelist dir="${dir}" files="1,2,3,4,5" />
+            </first>
+          </resourcecount>
+        </not>
+      </condition>
+    </fail>
+  </target>
+
+  <target name="first" depends="testfirst0,testfirst1,testfirst2" />
+
+  <target name="all" depends="legacy,files,resources,setlogic,single,first" />
 
 </project>

src/main/org/apache/tools/ant/types/defaults.properties

@@ -54,6 +54,7 @@ difference=org.apache.tools.ant.types.resources.Difference
 intersect=org.apache.tools.ant.types.resources.Intersect
 sort=org.apache.tools.ant.types.resources.Sort
 resources=org.apache.tools.ant.types.resources.Resources
+first=org.apache.tools.ant.types.resources.First
 
 #Resources (single-element ResourceCollections):
 resource=org.apache.tools.ant.types.Resource

src/main/org/apache/tools/ant/types/resources/BaseResourceCollectionWrapper.java

@@ -0,0 +1,203 @@
+/*
+ * Copyright 2005 The Apache Software Foundation
+ *
+ *  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.
+ *
+ */
+package org.apache.tools.ant.types.resources;
+
+import java.io.File;
+import java.util.List;
+import java.util.Stack;
+import java.util.Iterator;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+
+import org.apache.tools.ant.Project;
+import org.apache.tools.ant.BuildException;
+import org.apache.tools.ant.types.DataType;
+import org.apache.tools.ant.types.ResourceCollection;
+
+/**
+ * Base class for a ResourceCollection that wraps a single nested
+ * ResourceCollection.
+ * @since Ant 1.7
+ */
+public abstract class BaseResourceCollectionWrapper
+    extends DataType implements ResourceCollection, Cloneable {
+    private static final String ONE_NESTED_MESSAGE
+        = " expects exactly one nested resource collection.";
+
+    private ResourceCollection rc;
+    private Collection coll = null;
+    private boolean cache = true;
+
+    /**
+     * Set whether to cache collections.
+     * @param b boolean cache flag.
+     */
+    public synchronized void setCache(boolean b) {
+        cache = b;
+    }
+
+    /**
+     * Learn whether to cache collections. Default is <code>true</code>.
+     * @return boolean cache flag.
+     */
+    public synchronized boolean isCache() {
+        return cache;
+    }
+
+    /**
+     * Add a ResourceCollection to the container.
+     * @param c the ResourceCollection to add.
+     * @throws BuildException on error.
+     */
+    public synchronized void add(ResourceCollection c) throws BuildException {
+        if (isReference()) {
+            throw noChildrenAllowed();
+        }
+        if (c == null) {
+            return;
+        }
+        if (rc != null) {
+            throwOneNested();
+        }
+        rc = c;
+        setChecked(false);
+    }
+
+    /**
+     * Fulfill the ResourceCollection contract.
+     * @return an Iterator of Resources.
+     */
+    public synchronized final Iterator iterator() {
+        if (isReference()) {
+            return ((BaseResourceCollectionWrapper) getCheckedRef()).iterator();
+        }
+        dieOnCircularReference();
+        return cacheCollection().iterator();
+    }
+
+    /**
+     * Fulfill the ResourceCollection contract.
+     * @return number of elements as int.
+     */
+    public synchronized int size() {
+        if (isReference()) {
+            return ((BaseResourceCollectionWrapper) getCheckedRef()).size();
+        }
+        dieOnCircularReference();
+        return cacheCollection().size();
+    }
+
+    /**
+     * Fulfill the ResourceCollection contract.
+     * @return whether this is a filesystem-only resource collection.
+     */
+    public synchronized boolean isFilesystemOnly() {
+        if (isReference()) {
+            return ((BaseResourceCollectionContainer) getCheckedRef()).isFilesystemOnly();
+        }
+        dieOnCircularReference();
+
+        if (rc == null || rc.isFilesystemOnly()) {
+            return true;
+        }
+        /* now check each Resource in case the child only
+           lets through files from any children IT may have: */
+        for (Iterator i = cacheCollection().iterator(); i.hasNext();) {
+            if (!(i.next() instanceof FileResource)) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+    /**
+     * Overrides the version of DataType to recurse on all DataType
+     * child elements that may have been added.
+     * @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 stk, Project p)
+        throws BuildException {
+        if (isChecked()) {
+            return;
+        }
+        if (isReference()) {
+            super.dieOnCircularReference(stk, p);
+        } else {
+            if (rc instanceof DataType) {
+                stk.push(rc);
+                invokeCircularReferenceCheck((DataType) rc, stk, p);
+                stk.pop();
+            }
+            setChecked(true);
+        }
+    }
+
+    /**
+     * Get the nested ResourceCollection.
+     * @return a ResourceCollection.
+     * @throws BuildException if no nested ResourceCollection has been provided.
+     */
+    protected synchronized final ResourceCollection getResourceCollection() {
+        dieOnCircularReference();
+        if (rc == null) {
+            throwOneNested();
+        }
+        return rc;
+    }
+
+    /**
+     * Template method for subclasses to return a Collection of Resources.
+     * @return Collection.
+     */
+    protected abstract Collection getCollection();
+
+    /**
+     * Format this BaseResourceCollectionWrapper as a String.
+     * @return a descriptive <code>String</code>.
+     */
+    public synchronized String toString() {
+        if (isReference()) {
+            return getCheckedRef().toString();
+        }
+        if (cacheCollection().size() == 0) {
+            return "";
+        }
+        StringBuffer sb = new StringBuffer();
+        for (Iterator i = coll.iterator(); i.hasNext();) {
+            if (sb.length() > 0) {
+                sb.append(File.pathSeparatorChar);
+            }
+            sb.append(i.next());
+        }
+        return sb.toString();
+    }
+
+    private synchronized Collection cacheCollection() {
+        if (coll == null || !isCache()) {
+            coll = getCollection();
+        }
+        return coll;
+    }
+
+    private void throwOneNested() throws BuildException {
+        throw new BuildException(super.toString() + ONE_NESTED_MESSAGE);
+    }
+
+}

src/main/org/apache/tools/ant/types/resources/First.java

@@ -0,0 +1,72 @@
+/*
+ * Copyright 2005 The Apache Software Foundation
+ *
+ *  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.
+ *
+ */
+package org.apache.tools.ant.types.resources;
+
+import java.util.List;
+import java.util.Iterator;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+
+import org.apache.tools.ant.BuildException;
+import org.apache.tools.ant.types.ResourceCollection;
+
+/**
+ * ResourceCollection that contains the first <code>count</code> elements of
+ * another ResourceCollection.
+ * @since Ant 1.7
+ */
+public class First extends BaseResourceCollectionWrapper {
+    private static final String BAD_COUNT
+        = "count of first resources should be set to an int >= 0";
+
+    private int count = 1;
+
+    /**
+     * Set the number of resources to be included.
+     * @param i the count as <code>int</count>.
+     */
+    public synchronized void setCount(int i) {
+        count = i;
+    }
+
+    /**
+     * Get the number of resources to be included. Default is 1.
+     * @return the count as <code>int</count>.
+     */
+    public synchronized int getCount() {
+        return count;
+    }
+
+    /**
+     * Take the first <code>count</code> elements.
+     * @return a Collection of Resources.
+     */
+    protected Collection getCollection() {
+        int ct = getCount();
+        if (ct < 0) {
+            throw new BuildException(BAD_COUNT);
+        }
+        Iterator iter = getResourceCollection().iterator();
+        ArrayList al = new ArrayList(ct);
+        for (int i = 0; i < ct && iter.hasNext(); i++) {
+            al.add(iter.next());
+        }
+        return al;
+    }
+
+}

src/testcases/org/apache/tools/ant/types/ResourceCollectionsTest.java

@@ -73,6 +73,14 @@ public class ResourceCollectionsTest extends BuildFileTest {
         executeTarget("testfileurlref");
     }
 
+    public void testfirst1() {
+        executeTarget("testfirst1");
+    }
+
+    public void testfirst2() {
+        executeTarget("testfirst2");
+    }
+
     public void testhttpurl1() {
         executeTarget("testhttpurl1");
     }