geronimo-servlet_3.0_spec/src/main/java/javax/servlet/ServletResponseWrapper.java

/*
 * 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 javax.servlet;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.Locale;

/**
 * Provides a convenient implementation of the ServletResponse interface that
 * can be subclassed by developers wishing to adapt the response from a Servlet.
 * This class implements the Wrapper or Decorator pattern. Methods default to
 * calling through to the wrapped response object.
 *
 * @version $Rev$ $Date$
 * @see javax.servlet.ServletResponse
 * @since v 2.3
 */

public class ServletResponseWrapper implements ServletResponse {
    private ServletResponse response;

    /**
     * Creates a ServletResponse adaptor wrapping the given response object.
     *
     * @param response response to wrap
     * @throws java.lang.IllegalArgumentException
     *          if the response is null.
     */
    public ServletResponseWrapper(ServletResponse response) {
        if (response == null) {
            throw new IllegalArgumentException("Response cannot be null");
        }
        this.response = response;
    }

    /**
     * Return the wrapped ServletResponse object.
     *
     * @return wrapped response
     */
    public ServletResponse getResponse() {
        return this.response;
    }

    /**
     * Sets the response being wrapped.
     *
     * @param response response to wrap
     * @throws java.lang.IllegalArgumentException
     *          if the response is null.
     */
    public void setResponse(ServletResponse response) {
        if (response == null) {
            throw new IllegalArgumentException("Response cannot be null");
        }
        this.response = response;
    }

    /**
     * The default behavior of this method is to call setCharacterEncoding(String charset)
     * on the wrapped response object.
     *
     * @since 2.4
     */
    public void setCharacterEncoding(String charset) {
        this.response.setCharacterEncoding(charset);
    }

    /**
     * The default behavior of this method is to return getCharacterEncoding()
     * on the wrapped response object.
     */
    public String getCharacterEncoding() {
        return this.response.getCharacterEncoding();
    }

    /**
     * The default behavior of this method is to return getOutputStream()
     * on the wrapped response object.
     */
    public ServletOutputStream getOutputStream() throws IOException {
        return this.response.getOutputStream();
    }

    /**
     * The default behavior of this method is to return getWriter()
     * on the wrapped response object.
     */
    public PrintWriter getWriter() throws IOException {
        return this.response.getWriter();
    }

    /**
     * The default behavior of this method is to call setContentLength(int len)
     * on the wrapped response object.
     */
    public void setContentLength(int len) {
        this.response.setContentLength(len);
    }

    /**
     * The default behavior of this method is to call setContentType(String type)
     * on the wrapped response object.
     */
    public void setContentType(String type) {
        this.response.setContentType(type);
    }

    /**
     * The default behavior of this method is to return getContentType()
     * on the wrapped response object.
     *
     * @since 2.4
     */
    public String getContentType() {
        return this.response.getContentType();
    }

    /**
     * The default behavior of this method is to call setBufferSize(int size)
     * on the wrapped response object.
     */
    public void setBufferSize(int size) {
        this.response.setBufferSize(size);
    }

    /**
     * The default behavior of this method is to return getBufferSize()
     * on the wrapped response object.
     */
    public int getBufferSize() {
        return this.response.getBufferSize();
    }

    /**
     * The default behavior of this method is to call flushBuffer()
     * on the wrapped response object.
     */
    public void flushBuffer() throws IOException {
        this.response.flushBuffer();
    }

    /**
     * The default behavior of this method is to return isCommitted()
     * on the wrapped response object.
     */
    public boolean isCommitted() {
        return this.response.isCommitted();
    }

    /**
     * The default behavior of this method is to call reset()
     * on the wrapped response object.
     */
    public void reset() {
        this.response.reset();
    }

    /**
     * The default behavior of this method is to call resetBuffer()
     * on the wrapped response object.
     */
    public void resetBuffer() {
        this.response.resetBuffer();
    }

    /**
     * The default behavior of this method is to call setLocale(Locale loc)
     * on the wrapped response object.
     */
    public void setLocale(Locale loc) {
        this.response.setLocale(loc);
    }

    /**
     * The default behavior of this method is to return getLocale()
     * on the wrapped response object.
     */
    public Locale getLocale() {
        return this.response.getLocale();
    }

    public boolean isWrapperFor(Class wrappedType) {
        if (this.response.getClass().isAssignableFrom(wrappedType)) {
            return true;
        }
        if (this.response instanceof ServletResponseWrapper) {
            return ((ServletResponseWrapper)this.response).isWrapperFor(wrappedType);
        }
        return false;
    }

    public boolean isWrapperFor(ServletResponse instance) {
        if (instance == this.response) {
            return true;
        }
        if (this.response instanceof ServletResponseWrapper) {
            return ((ServletResponseWrapper)this.response).isWrapperFor(instance);
        }
        return false;
    }


}