com.bumptech.glide.load.model.LazyHeaders Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of glide Show documentation
Show all versions of glide Show documentation
A fast and efficient image loading library for Android focused on smooth scrolling.
package com.bumptech.glide.load.model;
import android.text.TextUtils;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
/**
* A wrapper class for a set of headers to be included in a Glide request, allowing headers to be
* constructed lazily.
*
* Ideally headers are constructed once and then re-used for multiple loads, rather then being
* constructed individually for each load.
*
* This class is thread safe.
*/
public final class LazyHeaders implements Headers {
private final Map> headers;
private volatile Map combinedHeaders;
LazyHeaders(Map> headers) {
this.headers = Collections.unmodifiableMap(headers);
}
@Override
public Map getHeaders() {
if (combinedHeaders == null) {
synchronized (this) {
if (combinedHeaders == null) {
this.combinedHeaders = Collections.unmodifiableMap(generateHeaders());
}
}
}
return combinedHeaders;
}
private Map generateHeaders() {
Map combinedHeaders = new HashMap();
for (Map.Entry> entry : headers.entrySet()) {
StringBuilder sb = new StringBuilder();
List factories = entry.getValue();
for (int i = 0; i < factories.size(); i++) {
LazyHeaderFactory factory = factories.get(i);
sb.append(factory.buildHeader());
if (i != factories.size() - 1) {
sb.append(',');
}
}
combinedHeaders.put(entry.getKey(), sb.toString());
}
return combinedHeaders;
}
@Override
public String toString() {
return "LazyHeaders{"
+ "headers=" + headers
+ '}';
}
@Override
public boolean equals(Object o) {
if (o instanceof LazyHeaders) {
LazyHeaders other = (LazyHeaders) o;
return headers.equals(other.headers);
}
return false;
}
@Override
public int hashCode() {
return headers.hashCode();
}
/**
* Builder class for {@link LazyHeaders}.
*
* This class is not thread safe.
*
* This class may include default values for User-Agent and Accept-Encoding headers. These
* will be replaced by calls to either {@link #setHeader(String, LazyHeaderFactory)} or
* {@link #addHeader(String, String)}, even though {@link #addHeader(String, LazyHeaderFactory)}
* would usually append an additional value.
*/
// PMD doesn't like the necessary static block to initialize DEFAULT_HEADERS.
@SuppressWarnings("PMD.FieldDeclarationsShouldBeAtStartOfClass")
public static final class Builder {
private static final String USER_AGENT_HEADER = "User-Agent";
private static final String DEFAULT_USER_AGENT = System.getProperty("http.agent");
private static final String ENCODING_HEADER = "Accept-Encoding";
private static final String DEFAULT_ENCODING = "identity";
private static final Map> DEFAULT_HEADERS;
// Set Accept-Encoding header to do our best to avoid gzip since it's both inefficient for
// images and also makes it more difficult for us to detect and prevent partial content
// rendering. See #440.
static {
Map> temp
= new HashMap>(2);
if (!TextUtils.isEmpty(DEFAULT_USER_AGENT)) {
temp.put(USER_AGENT_HEADER,
Collections.singletonList(
new StringHeaderFactory(DEFAULT_USER_AGENT)));
}
temp.put(ENCODING_HEADER,
Collections.singletonList(
new StringHeaderFactory(DEFAULT_ENCODING)));
DEFAULT_HEADERS = Collections.unmodifiableMap(temp);
}
private boolean copyOnModify = true;
private Map> headers = DEFAULT_HEADERS;
private boolean isEncodingDefault = true;
private boolean isUserAgentDefault = true;
/**
* Adds a value for the given header and returns this builder.
*
* Use {@link #addHeader(String, LazyHeaderFactory)} if obtaining the value requires I/O
* (ie an oauth token).
*
* @see #addHeader(String, LazyHeaderFactory)
*/
public Builder addHeader(String key, String value) {
return addHeader(key, new StringHeaderFactory(value));
}
/**
* Adds an {@link LazyHeaderFactory} that will be used to construct a value for the given
* key lazily on a background thread.
*
* Headers may have multiple values whose order is defined by the order in which
* this method is called.
*
* This class does not prevent you from adding the same value to a given key multiple
* times
*/
public Builder addHeader(String key, LazyHeaderFactory factory) {
if ((isEncodingDefault && ENCODING_HEADER.equalsIgnoreCase(key))
|| (isUserAgentDefault && USER_AGENT_HEADER.equalsIgnoreCase(key))) {
return setHeader(key, factory);
}
copyIfNecessary();
getFactories(key).add(factory);
return this;
}
/**
* Replaces all existing {@link LazyHeaderFactory LazyHeaderFactorys} for the given key
* with the given {@link LazyHeaderFactory}.
*
* If the given value is {@code null}, the header at the given key will be removed.
*
* Use {@link #setHeader(String, LazyHeaderFactory)} if obtaining the value requires I/O
* (ie an oauth token).
*/
public Builder setHeader(String key, String value) {
return setHeader(key, value == null ? null : new StringHeaderFactory(value));
}
/**
* Replaces all existing {@link LazyHeaderFactory LazyHeaderFactorys} for the given key
* with the given {@link LazyHeaderFactory}.
*
* If the given value is {@code null}, the header at the given key will be removed.
*/
public Builder setHeader(String key, LazyHeaderFactory factory) {
copyIfNecessary();
if (factory == null) {
headers.remove(key);
} else {
List factories = getFactories(key);
factories.clear();
factories.add(factory);
}
if (isEncodingDefault && ENCODING_HEADER.equalsIgnoreCase(key)) {
isEncodingDefault = false;
}
if (isUserAgentDefault && USER_AGENT_HEADER.equalsIgnoreCase(key)) {
isUserAgentDefault = false;
}
return this;
}
private List getFactories(String key) {
List factories = headers.get(key);
if (factories == null) {
factories = new ArrayList();
headers.put(key, factories);
}
return factories;
}
private void copyIfNecessary() {
if (copyOnModify) {
copyOnModify = false;
headers = copyHeaders();
}
}
/**
* Returns a new immutable {@link LazyHeaders} object.
*/
public LazyHeaders build() {
copyOnModify = true;
return new LazyHeaders(headers);
}
private Map> copyHeaders() {
Map> result =
new HashMap>(headers.size());
for (Map.Entry> entry : headers.entrySet()) {
result.put(entry.getKey(), new ArrayList(entry.getValue()));
}
return result;
}
}
static final class StringHeaderFactory implements LazyHeaderFactory {
private final String value;
StringHeaderFactory(String value) {
this.value = value;
}
@Override
public String buildHeader() {
return value;
}
@Override
public String toString() {
return "StringHeaderFactory{"
+ "value='" + value + '\''
+ '}';
}
@Override
public boolean equals(Object o) {
if (o instanceof StringHeaderFactory) {
StringHeaderFactory other = (StringHeaderFactory) o;
return value.equals(other.value);
}
return false;
}
@Override
public int hashCode() {
return value.hashCode();
}
}
}