Ant example source code file (PropertyResource.java)

This example Ant source code file (PropertyResource.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Ant tags/keywords

immutableresourceexception, inputstream, inputstream, io, ioexception, project, property_magic, propertyoutputstream, propertyresource, propertyresource, resource, resource, string, string, unset

The PropertyResource.java source code

/*
 *  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.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.ByteArrayInputStream;

import org.apache.tools.ant.Project;
import org.apache.tools.ant.types.Resource;
import org.apache.tools.ant.util.PropertyOutputStream;

/**
 * Exposes an Ant property as a Resource.
 * @since Ant 1.7
 */
public class PropertyResource extends Resource {

    /** Magic number */
    private static final int PROPERTY_MAGIC
        = Resource.getMagicNumber("PropertyResource".getBytes());

    private static final InputStream UNSET = new InputStream() {
        public int read() {
            return -1;
        }
    };

    /**
     * Default constructor.
     */
    public PropertyResource() {
    }

    /**
     * Construct a new PropertyResource with the specified name.
     * @param p the project to use.
     * @param n the String name of this PropertyResource (Ant property name/key).
     */
    public PropertyResource(Project p, String n) {
        super(n);
        setProject(p);
    }

    /**
     * Get the value of this PropertyResource.
     * @return the value of the specified Property.
     */
    public String getValue() {
        Project p = getProject();
        return p == null ? null : p.getProperty(getName());
    }

    /**
     * Find out whether this Resource exists.
     * @return true if the Property is set, false otherwise.
     */
    public boolean isExists() {
        return getValue() != null;
    }

    /**
     * Get the size of this Resource.
     * @return the size, as a long, 0 if the Resource does not exist (for
     *         compatibility with java.io.File), or UNKNOWN_SIZE if not known.
     */
    public long getSize() {
        if (isReference()) {
            return ((Resource) getCheckedRef()).getSize();
        }
        return isExists() ? (long) getValue().length() : 0L;
    }

    /**
     * Get the hash code for this Resource.
     * @return hash code as int.
     */
    public int hashCode() {
        if (isReference()) {
            return getCheckedRef().hashCode();
        }
        return super.hashCode() * PROPERTY_MAGIC;
    }

    /**
     * Get the string.
     *
     * @return the string contents of the resource.
     * @since Ant 1.7
     */
    public String toString() {
        if (isReference()) {
            return getCheckedRef().toString();
        }
        return String.valueOf(getValue());
    }

    /**
     * Get an InputStream for the Resource.
     * @return an InputStream containing this Resource's content.
     * @throws IOException if unable to provide the content of this
     *         Resource as a stream.
     * @throws UnsupportedOperationException if InputStreams are not
     *         supported for this Resource type.
     */
    public InputStream getInputStream() throws IOException {
        if (isReference()) {
            return ((Resource) getCheckedRef()).getInputStream();
        }
        return isExists() ? new ByteArrayInputStream(getValue().getBytes()) : UNSET;
    }

    /**
     * Get an OutputStream for the Resource.
     * @return an OutputStream to which content can be written.
     * @throws IOException if unable to provide the content of this
     *         Resource as a stream.
     * @throws UnsupportedOperationException if OutputStreams are not
     *         supported for this Resource type.
     */
    public OutputStream getOutputStream() throws IOException {
        if (isReference()) {
            return ((Resource) getCheckedRef()).getOutputStream();
        }
        if (isExists()) {
            throw new ImmutableResourceException();
        }
        return new PropertyOutputStream(getProject(), getName());
    }

}