diff options
Diffstat (limited to 'framework/src/ant/apache-ant-1.9.6/src/main/org/apache/tools/ant/types/resources/AbstractClasspathResource.java')
| -rw-r--r-- | framework/src/ant/apache-ant-1.9.6/src/main/org/apache/tools/ant/types/resources/AbstractClasspathResource.java | 265 |
1 files changed, 265 insertions, 0 deletions
diff --git a/framework/src/ant/apache-ant-1.9.6/src/main/org/apache/tools/ant/types/resources/AbstractClasspathResource.java b/framework/src/ant/apache-ant-1.9.6/src/main/org/apache/tools/ant/types/resources/AbstractClasspathResource.java new file mode 100644 index 00000000..417da9a7 --- /dev/null +++ b/framework/src/ant/apache-ant-1.9.6/src/main/org/apache/tools/ant/types/resources/AbstractClasspathResource.java @@ -0,0 +1,265 @@ +/* + * 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.tools.ant.types.resources; + +import java.io.FilterInputStream; +import java.io.IOException; +import java.io.InputStream; +import java.util.Stack; + +import org.apache.tools.ant.AntClassLoader; +import org.apache.tools.ant.Project; +import org.apache.tools.ant.types.Path; +import org.apache.tools.ant.types.Reference; +import org.apache.tools.ant.types.Resource; +import org.apache.tools.ant.util.FileUtils; + +/** + * + * A Resource representation of anything that is accessed via a Java classloader. + * The core methods to set/resolve the classpath are provided. + * @since Ant 1.8.0 + * + */ + +public abstract class AbstractClasspathResource extends Resource { + private Path classpath; + private Reference loader; + private boolean parentFirst = true; + + /** + * Set the classpath to use when looking up a resource. + * @param classpath to add to any existing classpath + */ + public void setClasspath(Path classpath) { + checkAttributesAllowed(); + if (this.classpath == null) { + this.classpath = classpath; + } else { + this.classpath.append(classpath); + } + setChecked(false); + } + + /** + * Add a classpath to use when looking up a resource. + * @return The classpath to be configured + */ + public Path createClasspath() { + checkChildrenAllowed(); + if (classpath == null) { + classpath = new Path(getProject()); + } + setChecked(false); + return classpath.createPath(); + } + + /** + * Set the classpath to use when looking up a resource, + * given as reference to a <path> defined elsewhere + * @param r The reference value + */ + public void setClasspathRef(Reference r) { + checkAttributesAllowed(); + createClasspath().setRefid(r); + } + + /** + * get the classpath used by this <code>LoadProperties</code>. + * @return The classpath + */ + public Path getClasspath() { + if (isReference()) { + return ((AbstractClasspathResource) getCheckedRef()).getClasspath(); + } + dieOnCircularReference(); + return classpath; + } + + /** + * Get the loader. + * @return the loader. + */ + public Reference getLoader() { + if (isReference()) { + return ((AbstractClasspathResource) getCheckedRef()).getLoader(); + } + dieOnCircularReference(); + return loader; + } + + /** + * Use the reference to locate the loader. If the loader is not + * found, taskdef will use the specified classpath and register it + * with the specified name. + * + * This allow multiple taskdef/typedef to use the same class loader, + * so they can be used together. It eliminate the need to + * put them in the CLASSPATH. + * + * @param r the reference to locate the loader. + */ + public void setLoaderRef(Reference r) { + checkAttributesAllowed(); + loader = r; + } + + /** + * Whether to consult the parent classloader first. + * + * <p>Only relevant if a classpath has been specified.</p> + * + * @since Ant 1.8.0 + */ + public void setParentFirst(boolean b) { + parentFirst = b; + } + + /** + * Overrides the super version. + * @param r the Reference to set. + */ + public void setRefid(Reference r) { + if (loader != null || classpath != null) { + throw tooManyAttributes(); + } + super.setRefid(r); + } + + /** + * Learn whether this resource exists. This implementation opens the input stream + * as the test. + * @return true if this resource exists. + */ + public boolean isExists() { + if (isReference()) { + return ((Resource) getCheckedRef()).isExists(); + } + dieOnCircularReference(); + InputStream is = null; + try { + is = getInputStream(); + return is != null; + } catch (IOException ex) { + return false; + } finally { + FileUtils.close(is); + } + } + + /** + * Return an InputStream for reading the contents of this Resource. + * @return an InputStream object. + * @throws IOException if an error occurs. + */ + public InputStream getInputStream() throws IOException { + if (isReference()) { + return ((Resource) getCheckedRef()).getInputStream(); + } + dieOnCircularReference(); + + final ClassLoaderWithFlag classLoader = getClassLoader(); + return !classLoader.needsCleanup() + ? openInputStream(classLoader.getLoader()) + : new FilterInputStream(openInputStream(classLoader.getLoader())) { + public void close() throws IOException { + FileUtils.close(in); + classLoader.cleanup(); + } + protected void finalize() throws Throwable { + try { + close(); + } finally { + super.finalize(); + } + } + }; + } + + /** + * combines the various ways that could specify a ClassLoader and + * potentially creates one that needs to be cleaned up when it is + * no longer needed so that classes can get garbage collected. + */ + protected ClassLoaderWithFlag getClassLoader() { + ClassLoader cl = null; + boolean clNeedsCleanup = false; + if (loader != null) { + cl = (ClassLoader) loader.getReferencedObject(); + } + if (cl == null) { + if (getClasspath() != null) { + Path p = getClasspath().concatSystemClasspath("ignore"); + if (parentFirst) { + cl = getProject().createClassLoader(p); + } else { + cl = AntClassLoader.newAntClassLoader(getProject() + .getCoreLoader(), + getProject(), + p, false); + } + clNeedsCleanup = loader == null; + } else { + cl = JavaResource.class.getClassLoader(); + } + if (loader != null && cl != null) { + getProject().addReference(loader.getRefId(), cl); + } + } + return new ClassLoaderWithFlag(cl, clNeedsCleanup); + } + + /** + * open the input stream from a specific classloader + * @param cl the classloader to use. Will be null if the system classloader is used + * @return an open input stream for the resource + * @throws IOException if an error occurs. + */ + protected abstract InputStream openInputStream(ClassLoader cl) throws IOException; + + protected synchronized void dieOnCircularReference(Stack<Object> stk, Project p) { + if (isChecked()) { + return; + } + if (isReference()) { + super.dieOnCircularReference(stk, p); + } else { + if (classpath != null) { + pushAndInvokeCircularReferenceCheck(classpath, stk, p); + } + setChecked(true); + } + } + + public static class ClassLoaderWithFlag { + private final ClassLoader loader; + private final boolean cleanup; + + ClassLoaderWithFlag(ClassLoader l, boolean needsCleanup) { + loader = l; + cleanup = needsCleanup && l instanceof AntClassLoader; + } + public ClassLoader getLoader() { return loader; } + public boolean needsCleanup() { return cleanup; } + public void cleanup() { + if (cleanup) { + ((AntClassLoader) loader).cleanup(); + } + } + } +} |