EnclosingMethodAttribute.java

/*******************************************************************************
 * Copyright (c) 1998, 2015 Oracle and/or its affiliates. All rights reserved.
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v1.0 and Eclipse Distribution License v. 1.0
 * which accompanies this distribution.
 * The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html
 * and the Eclipse Distribution License is available at
 * http://www.eclipse.org/org/documents/edl-v10.php.
 *
 * Contributors:
 *     Oracle - initial API and implementation from Oracle TopLink
******************************************************************************/
package org.eclipse.persistence.tools.workbench.utility.classfile;

import java.io.IOException;
import java.io.PrintWriter;
import java.io.Reader;
import java.io.StringReader;
import java.io.StringWriter;

import org.eclipse.persistence.tools.workbench.utility.classfile.descriptor.FieldType;
import org.eclipse.persistence.tools.workbench.utility.classfile.tools.ClassFileDataInputStream;
import org.eclipse.persistence.tools.workbench.utility.io.IndentingPrintWriter;


/**
 * This class models an enclosing method attribute:
 *     u2 attribute_name_index;
 *     u4 attribute_length;
 *     u2 class_index;
 *     u2 method_index;
 *
 * See "The Java Virtual Machine Specification" Chapter 4.
 */
public class EnclosingMethodAttribute extends Attribute {
    private short classIndex;
    private short methodIndex;

    private FieldType methodReturnDescriptor;        // lazy-initialized - so use the getter
    private FieldType[] methodParameterDescriptors;        // lazy-initialized - so use the getter


    /**
     * Construct an enclosing method attribute from the specified stream
     * of byte codes.
     */
    EnclosingMethodAttribute(ClassFileDataInputStream stream, short nameIndex, AttributePool pool) throws IOException {
        super(stream, nameIndex, pool);
    }

    void initializeInfo(ClassFileDataInputStream stream) throws IOException {
        this.classIndex = stream.readU2();
        this.methodIndex = stream.readU2();
    }

    void displayInfoStringOn(IndentingPrintWriter writer) {
        this.printFullyQualifiedMethodDeclarationOn(writer);
        writer.println();
    }

    public void printFullyQualifiedMethodDeclarationOn(PrintWriter writer) {
        writer.print(this.className());
        writer.print('.');
        if (this.methodIndex == 0) {
            writer.print("<static initialization>");
            return;
        }
        if (this.methodIsConstructor()) {
            writer.print(this.codeConstructorName());
        } else {
            writer.print(this.methodName());
        }
        writer.print('(');
        int len = this.getMethodParameterDescriptors().length;
        for (int i = 0; i < len; i++) {
            if (i != 0) {
                writer.write(", ");
            }
            this.getMethodParameterDescriptor(i).printDeclarationOn(writer);
        }
        writer.print(')');
    }

    public void accept(Visitor visitor) {
        visitor.visit(this);
        this.getMethodReturnDescriptor().accept(visitor);
        FieldType[] ptds = this.getMethodParameterDescriptors();
        int len = ptds.length;
        for (int i = 0; i < len; i++) {
            ptds[i].accept(visitor);
        }
    }

    /**
     * return the name of the constructor as it would appear in code
     */
    private String codeConstructorName() {
        String fullName = this.className();
        return fullName.substring(fullName.lastIndexOf('.') + 1);
    }

    public String fullyQualifiedSignature() {
        StringWriter sw = new StringWriter();
        PrintWriter pw = new PrintWriter(sw);
        this.printFullyQualifiedMethodDeclarationOn(pw);
        return sw.toString();
    }

    public String className() {
        return this.constantPool().getClassConstant(this.classIndex).name();
    }

    public String methodName() {
        NameAndTypeConstant mnatc = this.methodNameAndTypeConstant();
        return (mnatc == null) ? null : mnatc.name();
    }

    public String methodDescriptor() {
        NameAndTypeConstant mnatc = this.methodNameAndTypeConstant();
        return (mnatc == null) ? null : mnatc.descriptor();
    }

    public NameAndTypeConstant methodNameAndTypeConstant() {
        short index = this.methodIndex;
        return (index == 0) ? null : this.constantPool().getNameAndTypeConstant(index);
    }

    public short getClassIndex() {
        return this.classIndex;
    }

    public short getMethodIndex() {
        return this.methodIndex;
    }

    void toString(StringBuffer sb) {
        sb.append(this.fullyQualifiedSignature());
    }

    public boolean methodIsConstructor() {
        return this.methodName().equals(Method.CONSTRUCTOR_NAME);
    }

    public FieldType getMethodReturnDescriptor() {
        if (this.methodReturnDescriptor == null) {
            this.buildTypeDeclarations();
        }
        return this.methodReturnDescriptor;
    }

    public FieldType[] getMethodParameterDescriptors() {
        if (this.methodParameterDescriptors == null) {
            this.buildTypeDeclarations();
        }
        return this.methodParameterDescriptors;
    }

    public FieldType getMethodParameterDescriptor(int index) {
        if (this.methodParameterDescriptors == null) {
            this.buildTypeDeclarations();
        }
        return this.methodParameterDescriptors[index];
    }

    private void buildTypeDeclarations() {
        Reader reader = new StringReader(this.methodDescriptor());
        try {
            this.methodParameterDescriptors = Method.buildParameterDescriptors(reader);
            this.methodReturnDescriptor = FieldType.createFieldType(reader);
        } catch (IOException ex) {
            // this is unlikely when reading a String
            throw new RuntimeException(ex);
        }
    }

}