com.google.devtools.build.wireless.testing.java.injector.j2me.J2mePrintServant.java Source code

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Here is the source code for com.google.devtools.build.wireless.testing.java.injector.j2me.J2mePrintServant.java

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/*
 * Copyright 2007 Google Inc.
 *
 * 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 com.google.devtools.build.wireless.testing.java.injector.j2me;

import com.google.devtools.build.wireless.testing.java.injector.ClassNames;
import com.google.devtools.build.wireless.testing.java.injector.PrintServant;

import org.objectweb.asm.MethodVisitor;
import org.objectweb.asm.Opcodes;

/**
 * The PrintServant is injected into the J2ME application to log
 * relevant information.
 *
 * <p> The String is built with a {@link StringBuffer} because J2ME does
 * not have a {@link StringBuilder}.
 *
 * @author Michele Sama
 *
 */
public class J2mePrintServant extends PrintServant {

    protected String logIdentifier;

    /**
     * Creates an instance with a default log flag.
     *
     * @param mv The nested MethodVisitor.
     */
    public J2mePrintServant(MethodVisitor mv) {
        // TODO: Either improve or remove the default behavior.
        this(mv, "UI");
    }

    /**
     * Creates an instance which will log with the specified flag.
     *
     * @param mv The nested MethodVisitor.
     * @param logIdentifier The identifier to use while logging. Which can be
     * used to group related log events. e.g. "NETWORK".
     */
    public J2mePrintServant(MethodVisitor mv, String logIdentifier) {
        super(mv);
        this.logIdentifier = logIdentifier;
    }

    /**
     * Logs the new build string with the J2ME Logger.
     *
     * @see PrintServant#finalizePrinting()
     */
    @Override
    protected void finalizePrinting() {
        mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, ClassNames.STRING_BUFFER, "toString",
                "()L" + ClassNames.JAVA_LANG_STRING + ";");
        mv.visitLdcInsn(logIdentifier);
        mv.visitInsn(Opcodes.SWAP);
        mv.visitMethodInsn(Opcodes.INVOKESTATIC, J2meClassNames.LOG, "log",
                "(L" + ClassNames.JAVA_LANG_STRING + ";L" + ClassNames.JAVA_LANG_STRING + ";)V");
    }

    /**
     * Initialize a string buffer.
     *
     * @see PrintServant#initializePrinting()
     */
    @Override
    protected void initializePrinting() {
        mv.visitTypeInsn(Opcodes.NEW, ClassNames.STRING_BUFFER);
        mv.visitInsn(Opcodes.DUP);
        mv.visitMethodInsn(Opcodes.INVOKESPECIAL, ClassNames.STRING_BUFFER, "<init>", "()V");
    }

    /**
     * Prints the element on top of the stack by type.
     *
     * @see PrintServant#print(java.lang.String)
     */
    @Override
    public void print(String typeDesc) {
        String command = null;
        if (typeDesc.equals("")) {
            command = "L" + ClassNames.JAVA_LANG_STRING + ";";
        } else {
            command = typeToString(typeDesc);
        }

        mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, ClassNames.STRING_BUFFER, "append",
                "(" + command + ")L" + ClassNames.STRING_BUFFER + ";");
    }
}