org.attribyte.api.http.ResponseBuilder.java Source code

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Here is the source code for org.attribyte.api.http.ResponseBuilder.java

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/*
 * Copyright 2010,2014 Attribyte, LLC
 * 
 * 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.attribyte.api.http;

import com.google.common.base.Charsets;
import com.google.common.collect.Maps;
import com.google.common.io.ByteSource;
import com.google.common.io.ByteStreams;
import com.google.protobuf.ByteString;

import java.util.Collection;
import java.util.Map;

/**
 * Builds immutable HTTP responses.
 */
public class ResponseBuilder {

    /**
     * Creates a response builder.
     */
    public ResponseBuilder() {
    }

    /**
     * Creates a response builder with a response code.
     * @param statusCode The response code.
     */
    public ResponseBuilder(final int statusCode) {
        this.statusCode = statusCode;
    }

    /**
     * Creates a response builder with a response code and body as bytes.
     * @param statusCode The response code.
     * @param body The response body.
     */
    public ResponseBuilder(final int statusCode, final byte[] body) {
        this.statusCode = statusCode;
        this.body = body != null ? ByteString.copyFrom(body) : null;
    }

    /**
     * Creates a response builder with a response code and body as a string.
     * @param statusCode The response code.
     * @param body The response body.
     */
    public ResponseBuilder(final int statusCode, final String body) {
        this.statusCode = statusCode;
        this.body = body != null ? ByteString.copyFrom(body.getBytes(Charsets.UTF_8)) : null;
    }

    /**
     * Creates a response builder with a response code and body as a <code>ByteSource</code>.
     * @param statusCode The response code.
     * @param bodySource The response body source.
     */
    public ResponseBuilder(final int statusCode, final ByteSource bodySource) {
        this.statusCode = statusCode;
        this.bodySource = bodySource;
    }

    /**
     * Sets the response code.
     * @param statusCode The response code.
     * @return A self-reference.
     */
    public ResponseBuilder setStatusCode(final int statusCode) {
        this.statusCode = statusCode;
        return this;
    }

    /**
     * Sets the response body bytes.
     * @param body The body.
     * @return A self-reference.
     */
    public ResponseBuilder setBody(final byte[] body) {
        this.body = body != null ? ByteString.copyFrom(body) : null;
        return this;
    }

    /**
     * Sets the response body as a string.
     * @param body The body.
     * @return A self-reference.
     */
    public ResponseBuilder setBody(final String body) {
        this.body = body != null ? ByteString.copyFrom(body.getBytes(Charsets.UTF_8)) : null;
        return this;
    }

    /**
     * Sets a <code>ByteSource</code> for the response body.
     * @param body The body byte source.
     * @return A self-reference.
     */
    public ResponseBuilder setBody(ByteSource body) {
        this.bodySource = body;
        return this;
    }

    /**
     * Creates an immutable response.
     * @return The response.
     */
    public Response create() {
        return bodySource == null ? new BodyResponse(statusCode, headers, body, attributes)
                : new StreamedResponse(statusCode, headers, bodySource, attributes);
    }

    /**
     * Creates an immutable streamed response.
     * @return The response.
     */
    public StreamedResponse createStreamed() {
        final ByteSource bodySource = this.bodySource != null ? this.bodySource
                : body != null ? ByteSource.wrap(body.toByteArray()) : null;
        return new StreamedResponse(statusCode, headers, bodySource, attributes);
    }

    /**
     * Adds a header.
     * @param name The header name.
     * @param value The header value.
     * @return A self-reference.
     */
    public ResponseBuilder addHeader(final String name, final String value) {
        String lcName = name.toLowerCase();
        Header currHeader = headers.get(lcName);
        if (currHeader == null) {
            headers.put(lcName, new Header(name, value));
        } else {
            headers.put(lcName, currHeader.addValue(value));
        }
        return this;
    }

    /**
     * Adds a collection of headers.
     * @param headers The headers to add.
     * @return A self-reference.
     */
    public ResponseBuilder putHeaders(final Collection<Header> headers) {
        if (headers != null) {
            for (Header header : headers) {
                this.headers.put(header.getName().toLowerCase(), header);
            }
        }
        return this;
    }

    /**
     * Adds a map of headers.
     * @param headerMap The map of headers.
     * @return A self-reference.
     */
    public ResponseBuilder addHeaders(final Map<?, ?> headerMap) {
        if (headerMap != null) {
            this.headers.putAll(Header.createMap(headerMap));
        }
        return this;
    }

    /**
     * Adds an attribute.
     * @param name The attribute name.
     * @param object The attribute value.
     * @return A self-reference.
     */
    public ResponseBuilder addAttribute(final String name, final Object object) {
        maybeCreateAttributes().put(name, object);
        return this;
    }

    /**
     * Adds a map of attributes.
     * @param attributes The map of attributes.
     * @return A self-reference.
     */
    public ResponseBuilder addAttributes(final Map<String, Object> attributes) {
        if (attributes != null) {
            maybeCreateAttributes().putAll(attributes);
        }
        return this;
    }

    /**
     * Creates the attributes map if necessary.
     * @return The attributes.
     */
    private Map<String, Object> maybeCreateAttributes() {
        if (this.attributes == null) {
            this.attributes = Maps.newHashMapWithExpectedSize(4);
        }
        return this.attributes;
    }

    //Every response is going to have headers...
    final Map<String, Header> headers = Maps.newHashMapWithExpectedSize(8);
    //...but maybe will have attributes...
    Map<String, Object> attributes = null;
    ByteString body = null;
    ByteSource bodySource = null;
    //Constructors force this to be initialized to something...
    int statusCode;
}