/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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
 *
 *   https://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.apache.bcel.classfile;

import java.io.DataInput;
import java.io.DataOutputStream;
import java.io.IOException;
import java.util.Iterator;
import java.util.stream.Stream;

/**
 * base class for parameter annotations
 *
 * @since 6.0
 */
public abstract class ParameterAnnotations extends Attribute implements Iterable<ParameterAnnotationEntry> {

    private static final ParameterAnnotationEntry[] EMPTY_ARRAY = {};

    /** Table of parameter annotations */
    private ParameterAnnotationEntry[] parameterAnnotationTable;

    /**
     * Constructs a new instance.
     *
     * @param parameterAnnotationType the subclass type of the parameter annotation.
     * @param nameIndex Index pointing to the name <em>Code</em>.
     * @param length Content length in bytes.
     * @param input Input stream.
     * @param constantPool Array of constants.
     */
    ParameterAnnotations(final byte parameterAnnotationType, final int nameIndex, final int length, final DataInput input, final ConstantPool constantPool)
        throws IOException {
        this(parameterAnnotationType, nameIndex, length, (ParameterAnnotationEntry[]) null, constantPool);
        final int numParameters = input.readUnsignedByte();
        parameterAnnotationTable = new ParameterAnnotationEntry[numParameters];
        for (int i = 0; i < numParameters; i++) {
            parameterAnnotationTable[i] = new ParameterAnnotationEntry(input, constantPool);
        }
    }

    /**
     * Constructs a new instance.
     *
     * @param parameterAnnotationType the subclass type of the parameter annotation.
     * @param nameIndex Index pointing to the name <em>Code</em>.
     * @param length Content length in bytes.
     * @param parameterAnnotationTable the actual parameter annotations.
     * @param constantPool Array of constants.
     */
    public ParameterAnnotations(final byte parameterAnnotationType, final int nameIndex, final int length,
        final ParameterAnnotationEntry[] parameterAnnotationTable, final ConstantPool constantPool) {
        super(parameterAnnotationType, nameIndex, length, constantPool);
        this.parameterAnnotationTable = parameterAnnotationTable;
    }

    /**
     * Called by objects that are traversing the nodes of the tree implicitly defined by the contents of a Java class.
     * I.e., the hierarchy of methods, fields, attributes, etc. spawns a tree of objects.
     *
     * @param v Visitor object.
     */
    @Override
    public void accept(final Visitor v) {
        v.visitParameterAnnotation(this);
    }

    /**
     * @return deep copy of this attribute.
     */
    @Override
    public Attribute copy(final ConstantPool constantPool) {
        return (Attribute) clone();
    }

    @Override
    public void dump(final DataOutputStream dos) throws IOException {
        super.dump(dos);
        dos.writeByte(parameterAnnotationTable.length);

        for (final ParameterAnnotationEntry element : parameterAnnotationTable) {
            element.dump(dos);
        }

    }

    /**
     * returns the array of parameter annotation entries in this parameter annotation.
     */
    public ParameterAnnotationEntry[] getParameterAnnotationEntries() {
        return parameterAnnotationTable;
    }

    /**
     * @return the parameter annotation entry table.
     */
    public final ParameterAnnotationEntry[] getParameterAnnotationTable() {
        return parameterAnnotationTable;
    }

    @Override
    public Iterator<ParameterAnnotationEntry> iterator() {
        return Stream.of(parameterAnnotationTable).iterator();
    }

    /**
     * @param parameterAnnotationTable the entries to set in this parameter annotation.
     */
    public final void setParameterAnnotationTable(final ParameterAnnotationEntry[] parameterAnnotationTable) {
        this.parameterAnnotationTable = parameterAnnotationTable != null ? parameterAnnotationTable : EMPTY_ARRAY;
    }
}
