com.javanut.pronghorn.pipe.stream.StreamingReadVisitorToJSON Maven / Gradle / Ivy

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Ring buffer based queuing utility for applications that require high performance and/or a small footprint. Well suited for embedded and stream based processing.
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package com.javanut.pronghorn.pipe.stream;

import java.io.IOException;
import java.nio.Buffer;
import java.nio.ByteBuffer;

import com.javanut.pronghorn.util.Appendables;

public class StreamingReadVisitorToJSON implements StreamingReadVisitor {

	private final StringBuilder tempStringBuilder;
	private ByteBuffer tempByteBuffer;
	
	private A out;
	private int depth = 0;
	private int step = 2;
	private final boolean showBytesAsUTF;
	
	public StreamingReadVisitorToJSON(A out) {
		this(out, 4096, 256, false);
	}
	
	public StreamingReadVisitorToJSON(A out, boolean showBytesAsUTF) {
		this(out, 4096, 256, showBytesAsUTF);
	}
	
	public StreamingReadVisitorToJSON(A out, int maxBytesSize, int maxStringSize) {
		this(out,maxBytesSize, maxStringSize, false);
    }
	
	public StreamingReadVisitorToJSON(A out, int maxBytesSize, int maxStringSize, boolean showBytesAsUTF) {
	    this.out = out;
	    this.tempByteBuffer = ByteBuffer.allocate(maxBytesSize);
	    this.tempStringBuilder =  new StringBuilder(maxStringSize);
	    this.showBytesAsUTF = showBytesAsUTF;
	}
	
	
	@Override
	public boolean paused() {
		return false; //not used in this case because we block on out
	}

	private void writeTab() {
		try {
			int j = depth;
			while (--j>=0) {
				out.append(' ');
			}
		} catch (IOException e) {
			throw new RuntimeException(e);
		}	
	}
	
	@Override
	public void visitTemplateOpen(String name, long id) {
		//no tab needed here
		try {
			out.append("{\"").append(name).append("\":");
		} catch (IOException e) {
			throw new RuntimeException(e);
		}			
		depth = step;
	}
	
	@Override
	public void visitTemplateClose(String name, long id) {
		depth -= step;
		writeTab();
		try {
			out.append("}\n");
		} catch (IOException e) {
			throw new RuntimeException(e);
		}		
	}

	@Override
	public void visitFragmentOpen(String name, long id, int cursor) {
		writeTab();
		try{
			out.append("{\"").append(name).append("\":");	
		} catch (IOException e) {
			throw new RuntimeException(e);
		}		
		depth += step;
	}

	@Override
	public void visitFragmentClose(String name, long id) {
		depth -= step;
		writeTab();
		try {
			out.append("}");
		} catch (IOException e) {
			throw new RuntimeException(e);
		}	
	}

	@Override
	public void visitSequenceOpen(String name, long id, int length) {
		writeTab();
		try{
			out.append("[");
		} catch (IOException e) {
			throw new RuntimeException(e);
		}		
		depth += step;
	}

	@Override
	public void visitSequenceClose(String name, long id) {
		depth -= step;
		writeTab();
		try {
			out.append("]");
		} catch (IOException e) {
			throw new RuntimeException(e);
		}		
	}

	@Override
	public void visitSignedInteger(String name, long id, int value) {
		writeTab();
		try {
			out.append("{\"").append(name).append("\":");
			Appendables.appendValue(out, value);
			out.append("}");
		} catch (IOException e) {
			throw new RuntimeException(e);
		}		
	}

	@Override
	public void visitUnsignedInteger(String name, long id, long value) {
		writeTab();
		try {
			out.append("{\"").append(name).append("\":");
			Appendables.appendValue(out, value);
			out.append("}");
		} catch (IOException e) {
			throw new RuntimeException(e);
		}		
	}

	@Override
	public void visitSignedLong(String name, long id, long value) {
		writeTab();
		try {
			out.append("{\"").append(name).append("\":");
			Appendables.appendValue(out, value);
			out.append("}");
		} catch (IOException e) {
			throw new RuntimeException(e);
		}		
	}

	@Override
	public void visitUnsignedLong(String name, long id, long value) {
		writeTab();
		try {
			out.append("{\"").append(name).append("\":");
			//TODO: this is not strictly right and can be negative!!
			Appendables.appendValue(out, value);
			out.append("}"); 
		} catch (IOException e) {
			throw new RuntimeException(e);
		}		
	}

	@Override
	public void visitDecimal(String name, long id, int exp, long mant) {
		writeTab();
		try {
			out.append("{\"").append(name).append("\":[");
			Appendables.appendValue(out, exp).append(",");
			Appendables.appendValue(out, mant).append("]}");		
		} catch (IOException e) {
			throw new RuntimeException(e);
		}		
	}

	@Override
	public Appendable targetASCII(String name, long id) {
		tempStringBuilder.setLength(0);
		return tempStringBuilder;
	}

	@Override
	public void visitASCII(String name, long id, CharSequence value) {
		writeTab();
		try {
			out.append("{\"").append(name)
			   .append("\":\"")
			   .append(value)
			   .append("\"}");
		} catch (IOException e) {
			throw new RuntimeException(e);
		}	
	}

	@Override
	public Appendable targetUTF8(String name, long id) {
		tempStringBuilder.setLength(0);
		return tempStringBuilder;
	}

	@Override
	public void visitUTF8(String name, long id, CharSequence value) {
		writeTab();
		try {
			out.append("{\"");
	        out.append(name);
	        out.append("\":\"");
	        out.append(value);
			out.append("\"}");
		} catch (IOException e) {
			throw new RuntimeException(e);
		}	
	}

	@Override
	public ByteBuffer targetBytes(String name, long id, int length) {
		((Buffer)tempByteBuffer).clear();
		if (tempByteBuffer.capacity()