org.cryptoworkshop.ximix.common.asn1.message.PostedMessageBlock.java Source code

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Here is the source code for org.cryptoworkshop.ximix.common.asn1.message.PostedMessageBlock.java

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/**
 * Copyright 2013 Crypto Workshop Pty Ltd
 *
 * 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 org.cryptoworkshop.ximix.common.asn1.message;

import java.util.ArrayList;
import java.util.Collections;
import java.util.Enumeration;
import java.util.List;

import org.bouncycastle.asn1.ASN1EncodableVector;
import org.bouncycastle.asn1.ASN1Object;
import org.bouncycastle.asn1.ASN1Primitive;
import org.bouncycastle.asn1.ASN1Sequence;
import org.bouncycastle.asn1.DERSequence;

/**
 * Carrier class for a block of PostedMessage objects.
 */
public class PostedMessageBlock extends ASN1Object {
    private final List<PostedMessage> messages;

    /**
     * Builder for constructing a message block.
     */
    public static class Builder {
        private final List<PostedMessage> messages;
        private final int capacity;

        /**
         * Base constructor.
         *
         * @param capacity the maximum capacity for the message block we want to build.
         */
        public Builder(int capacity) {
            this.capacity = capacity;
            this.messages = new ArrayList<>(capacity);
        }

        public Builder add(int index, byte[] message) {
            messages.add(new PostedMessage(index, message));

            return this;
        }

        public Builder add(int index, byte[] message, byte[] commitment) {
            messages.add(new PostedMessage(index, message, commitment));

            return this;
        }

        public Builder clear() {
            messages.clear();

            return this;
        }

        public PostedMessageBlock build() {
            return new PostedMessageBlock(Collections.unmodifiableList(messages));
        }

        public int capacity() {
            return capacity;
        }

        public boolean isFull() {
            return messages.size() == capacity;
        }

        public boolean isEmpty() {
            return messages.isEmpty();
        }
    }

    private PostedMessageBlock(List<PostedMessage> messages) {
        this.messages = messages;
    }

    private PostedMessageBlock(ASN1Sequence seq) {
        messages = new ArrayList<>(seq.size());

        for (Enumeration en = seq.getObjects(); en.hasMoreElements();) {
            this.messages.add(PostedMessage.getInstance(en.nextElement()));
        }
    }

    public static final PostedMessageBlock getInstance(Object o) {
        if (o instanceof PostedMessageBlock) {
            return (PostedMessageBlock) o;
        } else if (o != null) {
            return new PostedMessageBlock(ASN1Sequence.getInstance(o));
        }

        return null;
    }

    @Override
    public ASN1Primitive toASN1Primitive() {
        ASN1EncodableVector v = new ASN1EncodableVector();

        for (PostedMessage message : messages) {
            v.add(message);
        }

        return new DERSequence(v);
    }

    public boolean hasCommitments() {
        return !messages.isEmpty() && messages.get(0).hasCommitment();
    }

    public List<PostedMessage> getMessages() {
        return messages;
    }

    public int size() {
        return messages.size();
    }
}