org.ros.message.MessageIdentifier.java Source code

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Here is the source code for org.ros.message.MessageIdentifier.java

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/*
 * Copyright (C) 2011 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 org.ros.message;

import com.google.common.base.Preconditions;

/**
 * Uniquely identifies a message.
 *
 * @author damonkohler@google.com (Damon Kohler)
 */
public class MessageIdentifier {

    private String type;
    private String pkg;
    private String name;

    public static MessageIdentifier of(String pkg, String name) {
        Preconditions.checkNotNull(pkg);
        Preconditions.checkNotNull(name);
        return new MessageIdentifier(pkg, name);
    }

    public static MessageIdentifier of(String type) {
        Preconditions.checkNotNull(type);
        // We're not using Preconditions.checkArgument() here because we want a
        // useful error message without paying the performance penalty of
        // constructing it every time.
        if (!type.contains("/")) {
            throw new IllegalArgumentException(
                    String.format("Type name is invalid or not fully qualified: \"%s\"", type));
        }
        return new MessageIdentifier(type);
    }

    private MessageIdentifier(String type) {
        this.type = type;
    }

    private MessageIdentifier(String pkg, String name) {
        this.pkg = pkg;
        this.name = name;
    }

    public String getType() {
        if (type == null) {
            // Using StringBuilder like this is about 40% faster than using the +
            // operator.
            StringBuilder stringBuilder = new StringBuilder(pkg.length() + name.length() + 1);
            stringBuilder.append(pkg);
            stringBuilder.append("/");
            stringBuilder.append(name);
            type = stringBuilder.toString();
        }
        return type;
    }

    private void splitType() {
        String[] packageAndName = type.split("/", 2);
        pkg = packageAndName[0];
        name = packageAndName[1];
    }

    public String getPackage() {
        if (pkg == null) {
            splitType();
        }
        return pkg;
    }

    public String getName() {
        if (name == null) {
            splitType();
        }
        return name;
    }

    @Override
    public String toString() {
        return String.format("MessageIdentifier<%s>", type);
    }

    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + ((type == null) ? 0 : type.hashCode());
        return result;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        MessageIdentifier other = (MessageIdentifier) obj;
        if (type == null) {
            if (other.type != null)
                return false;
        } else if (!type.equals(other.type))
            return false;
        return true;
    }
}