tapestry/tapestry-framework/src/java/org/apache/tapestry/IAsset.java

// Copyright 2004, 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.tapestry;

import java.io.InputStream;

import org.apache.hivemind.ApplicationRuntimeException;
import org.apache.hivemind.Locatable;
import org.apache.hivemind.Resource;

/**
 * Representation of a asset (GIF, JPEG, etc.) that may be owned by a {@link IComponent}.
 * <p>
 * Assets may be completely external (i.e., on some other web site), contained by the
 * {@link javax.servlet.ServletContext}, or stored somewhere in the classpath.
 * <p>
 * In the latter two cases, the resource may be localized.
 * 
 * @author Howard Lewis Ship
 */

public interface IAsset extends Locatable
{
    /**
     * Returns a URL for the asset, ready to be inserted into the output HTML. If the asset can be
     * localized, the localized version (matching the {@link java.util.Locale}of the current
     * {@link IPage page}) is returned.
     * 
     * @throws ApplicationRuntimeException
     *             if the asset does not exist.
     */

    String buildURL();

    /**
     * Accesses the localized version of the resource (if possible) and returns it as an input
     * stream. A version of the resource localized to the current {@link IPage page}is returned.
     * 
     * @throws ApplicationRuntimeException
     *             if the asset does not exist, or can't be read.
     */

    InputStream getResourceAsStream();

    /**
     * Returns the underlying location of the asset.
     */

    Resource getResourceLocation();
}