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/*
* FrameBuilder.java February 2014
*
* Copyright (C) 2014, Niall Gallagher <niallg@users.sf.net>
*
* 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.simpleframework.http.socket.service;
import java.util.Arrays;
import org.simpleframework.http.socket.DataConverter;
import org.simpleframework.http.socket.DataFrame;
import org.simpleframework.http.socket.Frame;
import org.simpleframework.http.socket.FrameType;
/**
* The <code>FrameBuilder</code> object is used to create an object
* that interprets a frame header to produce frame objects. For
* efficiency this converts binary data to the native frame data
* type, which avoids memory churn.
*
* @author Niall Gallagher
*
* @see org.simpleframework.http.socket.service.FrameConsumer
*/
class FrameBuilder {
/**
* This converts binary data to a UTF-8 string for text frames.
*/
private final DataConverter converter;
/**
* This is used to determine the type of frames to create.
*/
private final FrameHeader header;
/**
* Constructor for the <code>FrameBuilder</code> object. This acts
* as a factory for frame objects by using the provided header to
* determine the frame type to be created.
*
* @param header the header used to determine the frame type
*/
public FrameBuilder(FrameHeader header) {
this.converter = new DataConverter();
this.header = header;
}
/**
* This is used to create a frame object to represent the data that
* has been consumed. The frame created will contain either a copy of
* the provided byte buffer or a text string encoded in UTF-8. To
* avoid memory churn this method should be used sparingly.
*
* @return this returns a frame created from the consumed bytes
*/
public Frame create(byte[] data, int count) {
FrameType type = header.getType();
if(type.isText()) {
return createText(data, count);
}
return createBinary(data, count);
}
/**
* This is used to create a frame object from the provided data.
* The resulting frame will contain a UTF-8 encoding of the data
* to ensure that data conversion needs to be performed only once.
*
* @param data this is the data to convert to a new frame
* @param count this is the number of bytes in the frame
*
* @return a new frame containing the text
*/
private Frame createText(byte[] data, int count) {
FrameType type = header.getType();
String text = converter.convert(data, 0, count);
if(header.isFinal()) {
return new DataFrame(type, text, true);
}
return new DataFrame(type, text, false);
}
/**
* This is used to create a frame object from the provided data.
* The resulting frame will contain a copy of the data to ensure
* that the frame is immutable.
*
* @param data this is the data to convert to a new frame
* @param count this is the number of bytes in the frame
*
* @return a new frame containing a copy of the provided data
*/
private Frame createBinary(byte[] data, int count) {
FrameType type = header.getType();
byte[] copy = Arrays.copyOf(data, count);
if(header.isFinal()) {
return new DataFrame(type, copy, true);
}
return new DataFrame(type, copy, false);
}
}
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