Subclass of fileset which given a root class will return the closure of all

classes upon which that class depends.

Submitted by:	Holger Engels <hengels@mercatis.de>


git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@269884 13f79535-47bb-0310-9956-ffa450edef68

build.xml

@@ -36,7 +36,9 @@
   
   <property name="ant.package" value="org/apache/tools/ant"/>
   <property name="optional.package" value="${ant.package}/taskdefs/optional"/>
-  <property name="regexp.package" value="${ant.package}/util/regexp"/>
+  <property name="optional.type.package" value="${ant.package}/types/optional"/>
+  <property name="util.package" value="${ant.package}/util"/>
+  <property name="regexp.package" value="${util.package}/regexp"/>
 
   <property name="manifest" value="src/etc/manifest"/>
 
@@ -176,6 +178,9 @@
     <available property="xerces.present" 
                classname="org.apache.xerces.parsers.SAXParser" 
                classpathref="classpath" />
+    <available property="bcel.present" 
+               classname="de.fub.bytecode.Constants" 
+               classpathref="classpath" />
                
     <condition property="javamail.complete">
       <and>
@@ -284,6 +289,10 @@
       <exclude name="${optional.package}/metamata/**" unless="jdk1.2+" />
       <exclude name="${optional.package}/ManifestFile.java" 
                unless="jdk1.2+" />
+      <exclude name="${optional.type.package}/depend/*.java" 
+               unless="bcel.present" />
+      <exclude name="${util.package}/depend/*.java" 
+               unless="bcel.present" />
     </javac>
     
     <copy todir="${build.classes}">

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

@@ -5,4 +5,5 @@ patternset=org.apache.tools.ant.types.PatternSet
 mapper=org.apache.tools.ant.types.Mapper
 filterset=org.apache.tools.ant.types.FilterSet
 description=org.apache.tools.ant.types.Description
+classfileset=org.apache.tools.ant.types.optional.depend.ClassfileSet
 

src/main/org/apache/tools/ant/types/optional/depend/ClassfileSet.java

@@ -0,0 +1,102 @@
+/*
+ * The Apache Software License, Version 1.1
+ *
+ * Copyright (c) 2001 The Apache Software Foundation.  All rights
+ * reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * 3. The end-user documentation included with the redistribution, if
+ *    any, must include the following acknowlegement:
+ *       "This product includes software developed by the
+ *        Apache Software Foundation (http://www.apache.org/)."
+ *    Alternately, this acknowlegement may appear in the software itself,
+ *    if and wherever such third-party acknowlegements normally appear.
+ *
+ * 4. The names "The Jakarta Project", "Ant", and "Apache Software
+ *    Foundation" must not be used to endorse or promote products derived
+ *    from this software without prior written permission. For written
+ *    permission, please contact apache@apache.org.
+ *
+ * 5. Products derived from this software may not be called "Apache"
+ *    nor may "Apache" appear in their names without prior written
+ *    permission of the Apache Group.
+ *
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
+ * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
+ * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ * ====================================================================
+ *
+ * This software consists of voluntary contributions made by many
+ * individuals on behalf of the Apache Software Foundation.  For more
+ * information on the Apache Software Foundation, please see
+ * <http://www.apache.org/>.
+ */
+package org.apache.tools.ant.types.optional.depend;
+
+import java.io.File;
+import java.util.Stack;
+import org.apache.tools.ant.BuildException;
+import org.apache.tools.ant.DirectoryScanner;
+import org.apache.tools.ant.Project;
+import org.apache.tools.ant.types.FileSet;
+import org.apache.tools.ant.util.depend.Dependencies;
+
+/**
+ * A DepSet is a FileSet, that enlists all classes that depend on a
+ * certain class.
+ *
+ * A DependSet extends FileSets and uses another FileSet as input. The
+ * nested FileSet attribute provides the domain, that is used for searching
+ * for dependent classes
+ *
+ * @author <a href="mailto:hengels@innovidata.com">Holger Engels</a>
+ */
+public class ClassfileSet extends FileSet {
+    private File baseClass = null;
+
+    /**
+     * Set the directory for the fileset.  Prevents both "dir" and "src"
+     * from being specified.
+     */
+    public void setBaseClass(File baseClass)
+        throws BuildException
+    {
+        this.baseClass = baseClass;
+    }
+
+    public void setDir(File dir) throws BuildException {
+        super.setDir(dir);
+    }
+
+
+    /**
+     * Return the DirectoryScanner associated with this FileSet.
+     */
+    public DirectoryScanner getDirectoryScanner(Project p) {
+        DependScanner scanner = new DependScanner();
+        scanner.setBasedir(getDir(p));
+        scanner.setBaseClass(baseClass);
+        scanner.scan();
+        return scanner;
+    }    
+}

src/main/org/apache/tools/ant/types/optional/depend/DependScanner.java

@@ -0,0 +1,192 @@
+/*
+ * The Apache Software License, Version 1.1
+ *
+ * Copyright (c) 2001 The Apache Software Foundation.  All rights
+ * reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * 3. The end-user documentation included with the redistribution, if
+ *    any, must include the following acknowlegement:
+ *       "This product includes software developed by the
+ *        Apache Software Foundation (http://www.apache.org/)."
+ *    Alternately, this acknowlegement may appear in the software itself,
+ *    if and wherever such third-party acknowlegements normally appear.
+ *
+ * 4. The names "The Jakarta Project", "Ant", and "Apache Software
+ *    Foundation" must not be used to endorse or promote products derived
+ *    from this software without prior written permission. For written
+ *    permission, please contact apache@apache.org.
+ *
+ * 5. Products derived from this software may not be called "Apache"
+ *    nor may "Apache" appear in their names without prior written
+ *    permission of the Apache Group.
+ *
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
+ * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
+ * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ * ====================================================================
+ *
+ * This software consists of voluntary contributions made by many
+ * individuals on behalf of the Apache Software Foundation.  For more
+ * information on the Apache Software Foundation, please see
+ * <http://www.apache.org/>.
+ */
+package org.apache.tools.ant.types.optional.depend;
+
+import java.io.*;
+import java.util.*;
+
+import org.apache.tools.ant.util.depend.Dependencies;
+import org.apache.tools.ant.util.depend.Filter;
+import org.apache.tools.ant.DirectoryScanner;
+
+import de.fub.bytecode.classfile.*;
+import de.fub.bytecode.*;
+
+/**
+ * An interface used to describe the actions required by any type of 
+ * directory scanner.
+ */
+public class DependScanner extends DirectoryScanner {
+    File basedir;
+    File baseClass;
+    List included = new LinkedList();
+
+    /**
+     * Sets the basedir for scanning. This is the directory that is scanned
+     * recursively. 
+     *
+     * @param basedir the (non-null) basedir for scanning
+     */
+    public void setBasedir(String basedir) {
+        setBasedir(new File(basedir.replace('/',File.separatorChar).replace('\\',File.separatorChar)));
+    }
+
+    /**
+     * Sets the basedir for scanning. This is the directory that is scanned
+     * recursively.
+     *
+     * @param basedir the basedir for scanning
+     */
+    public void setBasedir(File basedir) {
+        this.basedir = basedir;
+    }
+    /**
+     * Gets the basedir that is used for scanning.
+     *
+     * @return the basedir that is used for scanning
+     */
+    public File getBasedir() { return basedir; }
+
+    /**
+     * Sets the domain, where dependant classes are searched
+     *
+     * @param domain the domain
+     */
+    public void setBaseClass(File baseClass) {
+        this.baseClass = baseClass;
+    }
+
+    /**
+     * Get the names of the class files, baseClass depends on
+     *
+     * @return the names of the files
+     */
+    public String[] getIncludedFiles() {
+        int count = included.size();
+        String[] files = new String[count];
+        for (int i = 0; i < count; i++) {
+            files[i] = included.get(i) + ".class";
+            //System.err.println("  " + files[i]);
+        }
+        return files;
+    }
+
+    /**
+     * Scans the base directory for files that baseClass depends on
+     *
+     * @exception IllegalStateException when basedir was set incorrecly
+     */
+    public void scan() {
+        Dependencies visitor = new Dependencies();
+        Set set = new TreeSet();
+        Set newSet = new HashSet();
+        final String base;
+        String start;
+        try {
+            base = basedir.getCanonicalPath() + File.separator;
+            start = baseClass.getCanonicalPath();
+        }
+        catch (Exception e) {
+            throw new IllegalArgumentException(e.getMessage());
+        }
+
+        start = start.substring(base.length(), start.length() - ".class".length()).replace(File.separatorChar, '/');
+        System.err.println("start: " + start);
+
+        newSet.add(start);
+        set.add(start);
+
+        do {
+            Iterator i = newSet.iterator();
+            while (i.hasNext()) {
+                String fileName = base + ((String)i.next()).replace('/', File.separatorChar) + ".class";
+
+                try {
+                    JavaClass javaClass = new ClassParser(fileName).parse();
+                    javaClass.accept(visitor);
+                }
+                catch (IOException e) {
+                    System.err.println("exception: " +  e.getMessage());
+                }
+            }
+            newSet.clear();
+            newSet.addAll(visitor.getDependencies());
+            visitor.clearDependencies();
+
+            Dependencies.applyFilter(newSet, new Filter() {
+                    public boolean accept(Object object) {
+                        String fileName = base + ((String)object).replace('/', File.separatorChar) + ".class";
+                        return new File(fileName).exists();
+                    }
+                });
+            newSet.removeAll(set);
+            set.addAll(newSet);
+        }
+        while (newSet.size() > 0);
+
+        included.clear();
+        included.addAll(set);
+    }
+
+    public void addDefaultExcludes() {}
+    public String[] getExcludedDirectories() { return null; };
+    public String[] getExcludedFiles() { return null; }
+    public String[] getIncludedDirectories() { return new String[0]; }
+    public String[] getNotIncludedDirectories() { return null; }
+    public String[] getNotIncludedFiles() { return null; }
+
+    public void setExcludes(String[] excludes) {}
+    public void setIncludes(String[] includes) {}
+    public void setCaseSensitive(boolean isCaseSensitive) {}
+}

src/main/org/apache/tools/ant/util/depend/Dependencies.java

@@ -0,0 +1,261 @@
+/*
+ * The Apache Software License, Version 1.1
+ *
+ * Copyright (c) 2001 The Apache Software Foundation.  All rights
+ * reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * 3. The end-user documentation included with the redistribution, if
+ *    any, must include the following acknowlegement:
+ *       "This product includes software developed by the
+ *        Apache Software Foundation (http://www.apache.org/)."
+ *    Alternately, this acknowlegement may appear in the software itself,
+ *    if and wherever such third-party acknowlegements normally appear.
+ *
+ * 4. The names "The Jakarta Project", "Ant", and "Apache Software
+ *    Foundation" must not be used to endorse or promote products derived
+ *    from this software without prior written permission. For written
+ *    permission, please contact apache@apache.org.
+ *
+ * 5. Products derived from this software may not be called "Apache"
+ *    nor may "Apache" appear in their names without prior written
+ *    permission of the Apache Group.
+ *
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
+ * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
+ * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ * ====================================================================
+ *
+ * This software consists of voluntary contributions made by many
+ * individuals on behalf of the Apache Software Foundation.  For more
+ * information on the Apache Software Foundation, please see
+ * <http://www.apache.org/>.
+ */
+package org.apache.tools.ant.util.depend;
+
+import java.io.*;
+import java.util.*;
+import de.fub.bytecode.classfile.*;
+import de.fub.bytecode.*;
+
+
+public class Dependencies implements Visitor {
+    private boolean verbose = false;
+
+    private JavaClass javaClass;
+    private ConstantPool constantPool;
+    private Set dependencies = new HashSet();
+
+    public void clearDependencies() {
+        dependencies.clear();
+    }
+    
+    public Set getDependencies() {
+        return dependencies;
+    }
+
+    public void visitCode(Code obj) {}
+    public void visitCodeException(CodeException obj) {}
+    
+    public void visitConstantClass(ConstantClass obj) {
+        if (verbose) {
+            System.out.println("visit ConstantClass");
+            System.out.println(obj.getConstantValue(constantPool));
+        }
+        dependencies.add("" + obj.getConstantValue(constantPool));
+    }
+    
+    public void visitConstantDouble(ConstantDouble obj) {}
+    public void visitConstantFieldref(ConstantFieldref obj) {}
+    public void visitConstantFloat(ConstantFloat obj) {}
+    public void visitConstantInteger(ConstantInteger obj) {}
+    public void visitConstantInterfaceMethodref(ConstantInterfaceMethodref obj) {}
+    public void visitConstantLong(ConstantLong obj) {}
+    public void visitConstantMethodref(ConstantMethodref obj) {}
+    public void visitConstantNameAndType(ConstantNameAndType obj) {}
+    
+    public void visitConstantPool(ConstantPool obj) {
+        if (verbose)
+            System.out.println("visit ConstantPool");
+        this.constantPool = obj;
+
+        // visit constants
+        for(int idx = 0; idx < constantPool.getLength(); idx++) {
+            Constant c = constantPool.getConstant(idx);
+            if (c != null) {
+                c.accept(this);
+            }
+        }
+    }
+    public void visitConstantString(ConstantString obj) {}
+    public void visitConstantUtf8(ConstantUtf8 obj) {}
+    public void visitConstantValue(ConstantValue obj) {}
+    public void visitDeprecated(Deprecated obj) {}
+    public void visitExceptionTable(ExceptionTable obj) {}
+    
+    public void visitField(Field obj) {
+        if (verbose) {
+            System.out.println("visit Field");
+            System.out.println(obj.getSignature());
+        }
+        addClasses(obj.getSignature());
+    }
+
+    public void visitInnerClass(InnerClass obj) {}
+    public void visitInnerClasses(InnerClasses obj) {}
+    
+    public void visitJavaClass(JavaClass obj) {
+        if (verbose) {
+            System.out.println("visit JavaClass");
+        }
+        
+        this.javaClass = obj;
+        dependencies.add(javaClass.getClassName().replace('.', '/'));
+
+        // visit constant pool
+        javaClass.getConstantPool().accept(this);
+
+        // visit fields
+        Field[] fields = obj.getFields();
+        for(int i=0; i < fields.length; i++) {
+            fields[i].accept(this);
+        }
+
+        // visit methods
+        Method[] methods = obj.getMethods();
+        for(int i=0; i < methods.length; i++) {
+            methods[i].accept(this);
+        }
+    }
+    public void visitLineNumber(LineNumber obj) {}
+    public void visitLineNumberTable(LineNumberTable obj) {}
+    public void visitLocalVariable(LocalVariable obj) {}
+    public void visitLocalVariableTable(LocalVariableTable obj) {}
+    
+    public void visitMethod(Method obj) {
+        if (verbose) {
+            System.out.println("visit Method");
+            System.out.println(obj.getSignature());
+        }
+        String signature = obj.getSignature();
+        int pos = signature.indexOf(")");
+        addClasses(signature.substring(1, pos));
+        addClasses(signature.substring(pos + 1));
+    }
+    
+    public void visitSourceFile(SourceFile obj) {}
+    public void visitSynthetic(Synthetic obj) {}
+    public void visitUnknown(Unknown obj) {}
+    public void visitStackMap(StackMap obj) {}
+    public void visitStackMapEntry(StackMapEntry obj) {}
+
+    void addClasses(String string) {
+        StringTokenizer tokens = new StringTokenizer(string, ";");
+        while (tokens.hasMoreTokens()) {
+            addClass(tokens.nextToken());
+        }
+    }
+
+    void addClass(String string) {
+        int pos = string.indexOf('L');
+        if (pos != -1) {
+            dependencies.add(string.substring(pos+1));
+        }
+    }
+
+    public static void main(String[] args) {
+        try {
+            Dependencies visitor = new Dependencies();
+
+            Set set = new TreeSet();
+            Set newSet = new HashSet();
+
+            int o=0;
+            String arg = null;
+            if ("-base".equals(args[0])) {
+                arg = args[1];
+                if (!arg.endsWith(File.separator)) {
+                    arg = arg + File.separator;
+                }
+                o=2;
+            }
+            final String base = arg;
+
+            for (int i=o; i < args.length; i++) {
+                String fileName = args[i].substring(0, args[i].length() - ".class".length());
+                if (base != null && fileName.startsWith(base))
+                    fileName = fileName.substring(base.length());
+                newSet.add(fileName);
+            }
+            set.addAll(newSet);
+
+            do {
+                Iterator i = newSet.iterator();
+                while (i.hasNext()) {
+                    String fileName = i.next() + ".class";
+
+                    if (base != null) {
+                        fileName = base + fileName;
+                    }
+
+                    JavaClass javaClass = new ClassParser(fileName).parse();
+                    javaClass.accept(visitor);
+                }
+                newSet.clear();
+                newSet.addAll(visitor.getDependencies());
+                visitor.clearDependencies();
+
+                applyFilter(newSet, new Filter() {
+                        public boolean accept(Object object) {
+                            String fileName = object + ".class";
+                            if (base != null)
+                                fileName = base + fileName;
+                            return new File(fileName).exists();
+                        }
+                    });
+                newSet.removeAll(set);
+                set.addAll(newSet);
+            }
+            while (newSet.size() > 0);
+
+            Iterator i = set.iterator();
+            while (i.hasNext()) {
+                System.out.println(i.next());
+            }
+        }
+        catch (Exception e) {
+            System.err.println(e.getMessage());
+            e.printStackTrace(System.err);
+        }
+    }
+
+    public static void applyFilter(Collection collection, Filter filter) {
+        Iterator i = collection.iterator();
+        while (i.hasNext()) {
+            Object next = i.next();
+            if (!filter.accept(next)) {
+                i.remove();
+            }
+        }
+    }
+}

src/main/org/apache/tools/ant/util/depend/Filter.java

@@ -0,0 +1,60 @@
+/*
+ * The Apache Software License, Version 1.1
+ *
+ * Copyright (c) 2001 The Apache Software Foundation.  All rights
+ * reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * 3. The end-user documentation included with the redistribution, if
+ *    any, must include the following acknowlegement:
+ *       "This product includes software developed by the
+ *        Apache Software Foundation (http://www.apache.org/)."
+ *    Alternately, this acknowlegement may appear in the software itself,
+ *    if and wherever such third-party acknowlegements normally appear.
+ *
+ * 4. The names "The Jakarta Project", "Ant", and "Apache Software
+ *    Foundation" must not be used to endorse or promote products derived
+ *    from this software without prior written permission. For written
+ *    permission, please contact apache@apache.org.
+ *
+ * 5. Products derived from this software may not be called "Apache"
+ *    nor may "Apache" appear in their names without prior written
+ *    permission of the Apache Group.
+ *
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
+ * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
+ * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ * ====================================================================
+ *
+ * This software consists of voluntary contributions made by many
+ * individuals on behalf of the Apache Software Foundation.  For more
+ * information on the Apache Software Foundation, please see
+ * <http://www.apache.org/>.
+ */
+package org.apache.tools.ant.util.depend;
+
+import java.util.*;
+
+public interface Filter {
+    boolean accept(Object object);
+}