de.codesourcery.jasm16.compiler.io.ClassPathResource.java Source code

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Here is the source code for de.codesourcery.jasm16.compiler.io.ClassPathResource.java

Source

package de.codesourcery.jasm16.compiler.io;

/**
 * Copyright 2012 Tobias Gierke <tobias.gierke@code-sourcery.de>
 *
 * 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.
 */

import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

import org.apache.commons.lang.StringUtils;

import de.codesourcery.jasm16.utils.ITextRegion;
import de.codesourcery.jasm16.utils.Misc;

/**
 * {@link IResource} implementation that wraps a resource from 
 * the classpath.
 * 
 * @author tobias.gierke@code-sourcery.de
 */
public class ClassPathResource extends AbstractResource {
    private final String classpathLocation;

    private byte[] contents;

    public ClassPathResource(String classpathLocation, ResourceType type) {
        super(type);

        if (StringUtils.isBlank(classpathLocation)) {
            throw new IllegalArgumentException("classpathLocation must not be NULL/blank");
        }
        this.classpathLocation = classpathLocation;
    }

    @Override
    public InputStream createInputStream() throws IOException {
        final InputStream stream = getClass().getClassLoader().getResourceAsStream(classpathLocation);
        if (stream == null) {
            throw new FileNotFoundException("Unable to load classpath resource '" + classpathLocation + "'");
        }
        return stream;
    }

    @Override
    public OutputStream createOutputStream(boolean append) throws IOException {
        throw new IOException("Cannot write to classpath resource '" + classpathLocation + "'");
    }

    private byte[] loadContents() throws IOException {
        if (contents == null) {
            contents = Misc.readBytes(this);
        }
        return contents;
    }

    @Override
    public String readText(ITextRegion range) throws IOException {
        loadContents();
        return range.apply(new String(contents));
    }

    @Override
    public String toString() {
        return classpathLocation;
    }

    @Override
    public long getAvailableBytes() throws IOException {
        loadContents();
        return this.contents.length;
    }

    @Override
    public String getIdentifier() {
        return classpathLocation;
    }
}