com.nginious.http.xsp.DocumentPart.java Source code

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Here is the source code for com.nginious.http.xsp.DocumentPart.java

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/**
 * Copyright 2012 NetDigital Sweden AB
 *
 * 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.nginious.http.xsp;

import java.util.HashMap;

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

/**
 * A document part represents a complete XSP page. All other parts are sub parts to an instance
 * of this part.
 * 
 * @author Bojan Pisler, NetDigital Sweden AB
 *
 */
public class DocumentPart extends ParentPart {

    private HashMap<String, MetaTagPart> metaTags;

    /**
     * Constructs a new document part with the specified XSP page source file path and
     * line number.
     * 
     * @param srcFilePath the XSP page source file path
     * @param lineNo the line number
     */
    DocumentPart(String srcFilePath, int lineNo) {
        super(srcFilePath, lineNo);
        this.metaTags = new HashMap<String, MetaTagPart>();
    }

    /**
     * Adds the specified sub tag part to this document tag part.
     * 
     * @param part the sub tag part to add
     */
    void addTagPart(TagPart part) {
        contentParts.add(part);
    }

    /**
     * Adds the specified meta tag part to this document tag part.
     * 
     * @param part the meta tag part to add
     */
    void addMetaTagPart(MetaTagPart part) {
        metaTags.put(part.getName(), part);
    }

    /**
     * Returns the meta tag with the specified name.
     * 
     * @param name the meta name
     * @return the meta value
     */
    String getMetaContent(String name) {
        MetaTagPart part = metaTags.get(name);

        if (part != null) {
            return part.getContent();
        }

        return null;
    }

    /**
     * Creates bytecode for this document tag part using the specified class writer and method visitor.
     * 
     * @param intClassName the binary class name of the class being created
     * @param writer the class writer
     * @param visitor the method visitor
     * @throws XspException if unable to create bytecode
     */
    void compile(String intClassName, ClassWriter writer, MethodVisitor visitor) throws XspException {
        // 0 = this, 1 = HttpRequest, 2 = HttpResponse, 3 = StringBuffer

        // StringBuffer buffer = new StringBuffer();
        visitor.visitTypeInsn(Opcodes.NEW, "java/lang/StringBuffer");
        visitor.visitInsn(Opcodes.DUP);
        visitor.visitMethodInsn(Opcodes.INVOKESPECIAL, "java/lang/StringBuffer", "<init>", "()V");
        visitor.visitVarInsn(Opcodes.ASTORE, 3);

        for (XspPart part : contentParts) {
            part.compile(intClassName, writer, visitor);
        }

        // response.setContentLength(buffer.length());
        visitor.visitVarInsn(Opcodes.ALOAD, 2);
        visitor.visitVarInsn(Opcodes.ALOAD, 3);
        visitor.visitMethodInsn(Opcodes.INVOKEVIRTUAL, "java/lang/StringBuffer", "length", "()I");
        visitor.visitMethodInsn(Opcodes.INVOKEINTERFACE, "com/nginious/http/HttpResponse", "setContentLength",
                "(I)V");

        // response.addHeader(contentType);
        String contentType = getMetaContent("Content-Type");

        if (contentType == null) {
            contentType = "application/unknown";
        }

        visitor.visitVarInsn(Opcodes.ALOAD, 2);
        visitor.visitLdcInsn("Content-Type");
        visitor.visitLdcInsn(contentType);
        visitor.visitMethodInsn(Opcodes.INVOKEINTERFACE, "com/nginious/http/HttpResponse", "addHeader",
                "(Ljava/lang/String;Ljava/lang/String;)V");

        // PrintWriter writer = response.getWriter();
        // writer.print(buffer.toString());
        visitor.visitVarInsn(Opcodes.ALOAD, 2);
        visitor.visitMethodInsn(Opcodes.INVOKEINTERFACE, "com/nginious/http/HttpResponse", "getWriter",
                "()Ljava/io/PrintWriter;");
        visitor.visitVarInsn(Opcodes.ALOAD, 3);
        visitor.visitMethodInsn(Opcodes.INVOKEVIRTUAL, "java/lang/StringBuffer", "toString",
                "()Ljava/lang/String;");
        visitor.visitMethodInsn(Opcodes.INVOKEVIRTUAL, "java/io/PrintWriter", "print", "(Ljava/lang/String;)V");
    }

    /**
     * Creates bytecode in a separate method for evaluating this document tag part.
     * 
     * @param intClassName the binary class name of the class being created
     * @param writer the class writer
     * @throws XspException if unable to create bytecode
     */
    void compileMethod(String intClassName, ClassWriter writer) throws XspException {
        for (XspPart part : this.contentParts) {
            part.compileMethod(intClassName, writer);
        }
    }
}